@article{ashwell_ceddia_house_cassady_eisen_eling_collins_grissom_odle_2010, title={Trans-10, cis-12-conjugated linoleic acid alters hepatic gene expression in a polygenic obese line of mice displaying hepatic lipidosis}, volume={21}, ISSN={["1873-4847"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77955844665&partnerID=MN8TOARS}, DOI={10.1016/j.jnutbio.2009.06.013}, abstractNote={The trans-10, cis-12 isomer of conjugated linoleic acid (CLA) causes a rapid reduction of body and adipose mass in mice. In addition to changes in adipose tissue, numerous studies have reported alterations in hepatic lipid metabolism. Livers of CLA-fed mice gain mass, partly due to lipid accumulation; however, the precise molecular mechanisms are unknown. To elucidate these mechanisms, we examined fatty acid composition and gene expression profiles of livers from a polygenic obese line of mice fed 1% trans-10, cis-12-CLA for 14 days. Analysis of gene expression data led to the identification of 1393 genes differentially expressed in the liver of CLA-fed male mice at a nominal P value of .01, and 775 were considered significant using a false discovery rate (FDR) threshold of .05. While surprisingly few genes in lipid metabolism were impacted, pathway analysis found that protein kinase A (PKA) and cyclic adenosine monophosphate (cAMP) pathways signaling pathways were affected by CLA treatment and 98 of the 775 genes were found to be regulated by hepatocyte nuclear factor 4α, a transcription factor important in controlling liver metabolic status.}, number={9}, journal={JOURNAL OF NUTRITIONAL BIOCHEMISTRY}, author={Ashwell, Melissa S. and Ceddia, Ryan P. and House, Ralph L. and Cassady, Joseph P. and Eisen, Eugene J. and Eling, Thomas E. and Collins, Jennifer B. and Grissom, Sherry F. and Odle, Jack}, year={2010}, month={Sep}, pages={848–855} } @article{eisen_2008, title={Can we rescue an endangered species?}, volume={125}, ISSN={["0931-2668"]}, DOI={10.1111/j.1439-0388.2008.00720.x}, abstractNote={The timely editorial by Ignacy Misztal (J. Anim. Breed. Genet., 124, 255–256) on the current shortage of quantitative geneticists in animal breeding is alarming. We in the field have been well aware of the problem for some time, but how to correct this trend is a formidable challenge. There are several reasons for the present situation. A major factor is that funding for research and training of graduate students in quantitative genetics and animal breeding (QGAB) began to decline as molecular genetics took center stage in the early 1990s. The prevailing view was that molecular genetics would soon solve all relevant problems in animal breeding. Experience has shown this assumption to be incorrect. Although molecular genetics has become a very important tool for understanding quantitative genetic variability, there are still many research questions that require a firm foundation in QGAB. There is a shortage of well-trained quantitative geneticists to meet all the demands of industry. It is imperative that government agencies and breeding companies that rely on qualified quantitative geneticists for their survival recognize the seriousness of the situation. Otherwise, the industry may soon find that the problem solvers trained in QGAB have become an extinct species. How then can we develop a plan to get QGAB off the endangered species list? Quantitative genetics is presently alive and well in areas other than animal breeding. For example, evolutionary biology and human genetics draw heavily on the discipline of quantitative genetics, and these fields are successfully training quantitative geneticists. I recently participated in a Gordon Conference on Quantitative Genetics that was well attended by colleagues and graduate students in evolutionary biology and genetics. Of note were several researchers who have ‘jumped ship’ from animal breeding to human genetics. While the reasons for making the change are complex, the lack of adequate funding for QGAB research most certainly played a role in their decision. To develop a plan to get QGAB off the endangered species list, at least four general factors must be addressed: (i) government funding, (ii) industry support, (iii) grooming undergraduates and (iv) recruiting and funding graduate students. Government agencies that traditionally fund agriculturally related research, as well as legislators that have a strong commitment to agriculture, must be apprised of the economic impact of QGAB research. To do so most effectively, professional societies such as the American Society of Animal Science and the European Association for Animal Production should appoint a commission of experts to study the problem and make appropriate recommendations to federal funding agencies on the importance of funding research and graduate training in QGAB. In this regard, the commission should look at the global picture of how past research in QGAB has improved the genetic quality and yield of food and fiber obtained from domestic animals, including aquatic species such as oysters and shrimp. Quantitative geneticists in animal breeding are specifically trained in aspects of application to animal genetic improvement that are generally not in the purview of molecular biologists. For this reason, the commission should also explore the economic benefits for research collaborations between well-trained quantitative geneticists and molecular geneticists. This point is particularly relevant in light of the current push to complete the gene sequencing of food animal species. Federal agencies generally have a policy of limiting research funding under specific headings. For example, in the United States, the United States Department of Agriculture funds agricultural research whereas the National Science Foundation (NSF) has generally funded only basic research to the exclusion of research in agriculture. However, in recent years NSF has begun to fund plant genetics research that might in the broad sense be considered to have application to plant breeding. Therefore, it is certainly conceivable that NSF might be persuaded to focus on funding certain aspects of quantitative genetics research applied to food animal species that bridges the basic-applied spectrum. The support of industry is vital if QGAB is to survive. This support can take on many forms. It should include funding for QGAB research that is related to both the goals of the breeding industry and to answering more basic questions, funding for graduate student assistantship stipends and specialized short courses, sharing of data that can be used for M.S. and Ph.D. dissertations and sponsoring summer internships for undergraduates. While many companies participate in these types of activities, their participation needs to be more widespread to have a greater impact. It would be worthwhile to have some statistics available on the level of support provided by industry. Enticing bright undergraduate students to consider a career in QGAB is challenging because of competition from other fields. This is particularly so among animal science students. The profile of animal science undergraduate students at many land grant universities in the United States has changed dramatically in recent years. The majority of students now are women, most come from urban or suburban areas and the number one career goal of the majority of entering students is veterinary medicine specializing in companion animals. Among those interested in graduate school, there is strong competition from the fields of nutrition, reproductive physiology and molecular genetics. To steer undergraduates into a career in QGAB, the first step is to advise them to do an undergraduate research project, preferably under the direction of a faculty member in QGAB. A research experience with laboratory animals can be just as effective as one using economic species, particularly given the length of time a student can devote to a research project. The research should be designed to be completed within an academic year and provide sufficient substance so that the research results can be presented at an undergraduate poster programme and perhaps even at a regional or national professional scientific meeting. Also essential is advising students interested in QGAB to take appropriate courses in genetics, animal breeding, calculus, matrix algebra and statistics and to attend research seminars. Finally, the student should participate in at least one summer internship with a breeding company or in a QGAB research laboratory. I believe the final point, recruiting outstanding graduate students, is perhaps the most critical issue. Recruiting top-quality students will be made easier as we groom those outstanding undergraduates in the manner suggested and if adequate funding for graduate student stipends begins to flow from federal grants and industry. The training of graduate students is perhaps our most urgent issue because of the time involved; 3–5 years toward a Ph.D. plus 1–2 years of postdoctoral experience are involved before germination of the seeds that are essential to get QGAB off the endangered species list. I believe the time has come for the actions needed to begin planting these seeds.}, number={1}, journal={JOURNAL OF ANIMAL BREEDING AND GENETICS}, author={Eisen, Eugene J.}, year={2008}, month={Feb}, pages={1–2} } @article{eisen_2007, title={Animal breeding: What does the future hold?}, volume={20}, ISSN={["1976-5517"]}, DOI={10.5713/ajas.2007.453}, abstractNote={An overview of developments important in the future of animal breeding is discussed. Examples from the application of quantitative genetic principles to selection in chickens and mice are given. Lessons to be learned from these species are that selection for production traits in livestock must also consider selection for reproduction and other fitness-related traits and inbreeding should be minimized. Short-term selection benefits of best linear unbiased predictor methodology must be weighed against long-term risks of increased rate of inbreeding. Different options have been developed to minimize inbreeding rates while maximizing selection response. Development of molecular genetic methods to search for quantitative trait loci provides the opportunity for incorporating marker-assisted selection and introgression as new tools for increasing efficiency of genetic improvement. Theoretical and computer simulation studies indicate that these methods hold great promise once genotyping costs are reduced to make the technology economically feasible. Cloning and transgenesis are not likely to contribute significantly to genetic improvement of livestock production in the near future.}, number={3}, journal={ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES}, author={Eisen, E. J.}, year={2007}, month={Mar}, pages={453–460} } @article{yi_zinniel_kim_eisen_bartolucci_allison_pomp_2006, title={Bayesian analyses of multiple epistatic QTL models for body weight and body composition in mice}, volume={87}, ISSN={["1469-5073"]}, DOI={10.1017/S0016672306007944}, abstractNote={To comprehensively investigate the genetic architecture of growth and obesity, we performed Bayesian analyses of multiple epistatic quantitative trait locus (QTL) models for body weights at five ages (12 days, 3, 6, 9 and 12 weeks) and body composition traits (weights of two fat pads and five organs) in mice produced from a cross of the F1 between M16i (selected for rapid growth rate) and CAST/Ei (wild-derived strain of small and lean mice) back to M16i. Bayesian model selection revealed a temporally regulated network of multiple QTL for body weight, involving both strong main effects and epistatic effects. No QTL had strong support for both early and late growth, although overlapping combinations of main and epistatic effects were observed at adjacent ages. Most main effects and epistatic interactions had an opposite effect on early and late growth. The contribution of epistasis was more pronounced for body weights at older ages. Body composition traits were also influenced by an interacting network of multiple QTLs. Several main and epistatic effects were shared by the body composition and body weight traits, suggesting that pleiotropy plays an important role in growth and obesity.}, number={1}, journal={GENETICS RESEARCH}, author={Yi, NJ and Zinniel, DK and Kim, K and Eisen, EJ and Bartolucci, A and Allison, DB and Pomp, D}, year={2006}, month={Feb}, pages={45–60} } @article{blowe_boyette_ashwell_eisen_robison_cassady_2006, title={Characterization of a line of pigs previously selected for increased litter size for RBP4 and follistatin}, volume={123}, ISSN={["1439-0388"]}, DOI={10.1111/j.1439-0388.2006.00620.x}, abstractNote={SummaryThe objective of this study was to determine if selection response for increased litter size in pigs could be partially attributed to three type 1 marker loci coding for genes known to affect litter size: oestrogen receptor (ESR), retinol‐binding protein 4 (RBP4) and follistatin (FS). In the high litter size line (LS), pigs from the largest litters, based on number of pigs born alive (NBA), were retained to parent the next generation. A randomly selected control line (LC) was maintained. Gilts were reared in litters of 10 pigs or less to minimize maternal effects. Pigs were measured at generations 10–12. Additional traits scored were number of fully formed pigs (NFF) and number of mummified fetuses (MUM). Breeding values for NFF and NBA were greater (p < 0.05) in LS than LC in generations 11 and 12, but no significant line differences were found for MUM. The A allele of the ESR locus was fixed in both lines. After adjustment for effects of genetic drift, frequency of the two alleles segregating for the FS and RBP4 loci did not differ significantly between lines. No significant additive or dominance effects of the FS markers were detected for NFF, NBA and MUM in either LS or LC. Response to selection for increased litter size could not be attributed to effects at the ESR, RBP4 or FS loci.}, number={6}, journal={JOURNAL OF ANIMAL BREEDING AND GENETICS}, author={Blowe, C. D. and Boyette, K. E. and Ashwell, M. S. and Eisen, E. J. and Robison, O. W. and Cassady, J. P.}, year={2006}, month={Dec}, pages={389–395} } @article{wolf_pomp_eisen_cheverud_leamy_2006, title={The contribution of epistatic pleiotropy to the genetic architecture of covariation among polygenic traits in mice}, volume={8}, ISSN={["1520-541X"]}, DOI={10.1111/j.1525-142X.2006.00120.x}, abstractNote={SUMMARYThe contribution that pleiotropic effects of individual loci make to covariation among traits is well understood theoretically and is becoming well documented empirically. However, little is known about the role of epistasis in determining patterns of covariation among traits. To address this problem we combine a quantitative trait locus (QTL) analysis with a two‐locus model to assess the contribution of epistasis to the genetic architecture of variation and covariation of organ weights and limb bone lengths in a backcross population of mice created from the M16i and CAST/Ei strains. Significant epistasis was exhibited by 14 pairwise combinations of QTL for organ weights and 10 combinations of QTL for limb bone lengths, which contributed, on average, about 5% of the variation in organ weights and 8% in limb bone lengths beyond that of single‐locus QTL effects. Epistatic pleiotropy was much more common in the limb bones (seven of 10 epistatic combinations affecting limb bone lengths were pleiotropic) than the organs (three of the 14 epistatic combinations affecting organ weights were pleiotropic). In both cases, epistatic pleiotropy was less common than single‐locus pleiotropy. Epistatic pleiotropy accounted for an average of 6% of covariation among organ weights and 21% of covariation among limb bone lengths, which represented an average of one‐fifth (for organ weights) and one‐third (for limb bone lengths) of the total genetic covariance between traits. Thus, although epistatic pleiotropy made a smaller contribution than single‐locus pleiotropy, it clearly made a significant contribution to the genetic architecture of variation/covariation.}, number={5}, journal={EVOLUTION & DEVELOPMENT}, author={Wolf, Jason B. and Pomp, Daniel and Eisen, Eugene J. and Cheverud, James M. and Leamy, Larry J.}, year={2006}, pages={468–476} } @article{yi_yandell_churchill_allison_eisen_pomp_2005, title={Bayesian model selection for genome-wide epistatic quantitative trait loci analysis}, volume={170}, ISSN={["1943-2631"]}, DOI={10.1534/genetics.104.040386}, abstractNote={Abstract The problem of identifying complex epistatic quantitative trait loci (QTL) across the entire genome continues to be a formidable challenge for geneticists. The complexity of genome-wide epistatic analysis results mainly from the number of QTL being unknown and the number of possible epistatic effects being huge. In this article, we use a composite model space approach to develop a Bayesian model selection framework for identifying epistatic QTL for complex traits in experimental crosses from two inbred lines. By placing a liberal constraint on the upper bound of the number of detectable QTL we restrict attention to models of fixed dimension, greatly simplifying calculations. Indicators specify which main and epistatic effects of putative QTL are included. We detail how to use prior knowledge to bound the number of detectable QTL and to specify prior distributions for indicators of genetic effects. We develop a computationally efficient Markov chain Monte Carlo (MCMC) algorithm using the Gibbs sampler and Metropolis-Hastings algorithm to explore the posterior distribution. We illustrate the proposed method by detecting new epistatic QTL for obesity in a backcross of CAST/Ei mice onto M16i.}, number={3}, journal={GENETICS}, author={Yi, NJ and Yandell, BS and Churchill, GA and Allison, DB and Eisen, EJ and Pomp, D}, year={2005}, month={Jul}, pages={1333–1344} } @misc{house_cassady_eisen_mcintosh_odle_2005, title={Conjugated linoleic acid evokes de-lipidation through the regulation of genes controlling lipid metabolism in adipose and liver tissue}, volume={6}, ISSN={["1467-789X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-22744451979&partnerID=MN8TOARS}, DOI={10.1111/j.1467-789X.2005.00198.x}, abstractNote={SummaryConjugated linoleic acid (CLA) is a unique lipid that elicits dramatic reductions in adiposity in several animal models when included at ≤ 1% of the diet. Despite a flurry of investigations, the precise mechanisms by which conjugated linoleic acid elicits its dramatic effects in adipose tissue and liver are still largely unknown. In vivo and in vitro analyses of physiological modifications imparted by conjugated linoleic acid on protein and gene expression suggest that conjugated linoleic acid exerts its de‐lipidating effects by modulating energy expenditure, apoptosis, fatty acid oxidation, lipolysis, stromal vascular cell differentiation and lipogenesis. The purpose of this review shall be to examine the recent advances and insights into conjugated linoleic acid's effects on obesity and lipid metabolism, specifically focused on changes in gene expression and physiology of liver and adipose tissue.}, number={3}, journal={OBESITY REVIEWS}, author={House, RL and Cassady, JP and Eisen, EJ and McIntosh, MK and Odle, J}, year={2005}, month={Aug}, pages={247–258} } @article{jerez-timaure_eisen_pomp_2005, title={Fine mapping of a QTL region with large effects on growth and fatness on mouse chromosome 2}, volume={21}, ISSN={["1531-2267"]}, DOI={10.1152/physiolgenomics.00256.2004}, abstractNote={We combined the use of a congenic line and recombinant progeny testing (RPT) to characterize and fine map a previously identified region of distal mouse chromosome 2 (MMU2) harboring quantitative trait loci (QTL) with large effects on growth and fatness. The congenic line [M16i.B6-( D2Mit306- D2Mit52); MB2] was created using an inbred line (M16i) derived from a line that had undergone long-term selection for rapid weight gain (M16) as the recipient for an ∼38-cM region on MMU2 from the inbred line C57BL/6J. A large F2cohort (1,200 mice) originating from a cross between MB2 and M16i was created, and 40 F2males with defined recombinations within the QTL region were used to produce 665 segregating progeny. Linkage analysis of the F2population detected QTL with very large effects on body weight, body fat, lean tissue mass, bone mineral density, and liver weight. Confidence intervals of the QTL were narrowed to regions of 1.5–4.5 cM. Analysis of progeny of the recombinant F2males confirmed the existence of the QTL and further contributed to localization of their map positions. These efforts confirmed the presence of QTL with major effect on MMU2, narrowed the estimated region harboring the QTL from 38 to 12 cM, and further characterized phenotypic effects of the QTL, effectively culminating in a significantly decreased pool of positional candidate genes potentially representing these genes controlling predisposition to growth and fatness.}, number={3}, journal={PHYSIOLOGICAL GENOMICS}, author={Jerez-Timaure, NC and Eisen, EJ and Pomp, D}, year={2005}, month={May}, pages={411–422} } @article{house_cassady_eisen_eling_collins_grissom_odle_2005, title={Functional genomic characterization of delipidation elicited by trans-10, cis-12-conjugated linoleic acid (t10c12-CLA) in a polygenic obese line of mice}, volume={21}, ISSN={["1531-2267"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-21244497638&partnerID=MN8TOARS}, DOI={10.1152/physiolgenomics.00244.2004}, abstractNote={Gene expression was measured during t10c12-CLA-induced body fat reduction in a polygenic obese line of mice. Adult mice ( n = 185) were allotted to a 2 × 2 factorial experiment consisting of either nonobese (ICR-control) or obese (M16-selected) mice fed a 7% fat, purified diet containing either 1% linoleic acid (LA) or 1% t10c12-CLA. Body weight (BW) by day 14 was 12% lower in CLA- compared with LA-fed mice ( P < 0.0001). By day 14, t10c12-CLA reduced weights of epididymal, mesenteric, and brown adipose tissues, as a percentage of BW, in both lines by 30, 27, and 58%, respectively, and increased liver weight/BW by 34% ( P < 0.0001). Total RNA was isolated and pooled (4 pools per tissue per day) from epididymal adipose ( days 5 and 14) of the obese mice to analyze gene expression profiles using Agilent mouse oligo microarray slides representing >20,000 genes. Numbers of genes differentially expressed by greater than or equal to twofold in epididymal adipose ( days 5 and 14) were 29 and 125, respectively. It was concluded that, in adipose tissue, CLA increased expression of uncoupling proteins (1 and 2), carnitine palmitoyltransferase system, tumor necrosis factor-α ( P < 0.05), and caspase-3 but decreased expression of peroxisome proliferator-activated receptor-γ, glucose transporter-4, perilipin, caveolin-1, adiponectin, resistin, and Bcl-2 ( P < 0.01). In conclusion, this experiment has revealed candidate genes that will be useful in elucidating mechanisms of adipose delipidation.}, number={3}, journal={PHYSIOLOGICAL GENOMICS}, author={House, RL and Cassady, JP and Eisen, EJ and Eling, TE and Collins, JB and Grissom, SF and Odle, J}, year={2005}, month={May}, pages={351–361} } @article{allan_eisen_pomp_2005, title={Genomic mapping of direct and correlated responses to long-term selection for rapid growth rate in mice}, volume={170}, DOI={10.1534/genetics.105.041319}, abstractNote={Abstract Understanding the genetic architecture of traits such as growth, body composition, and energy balance has become a primary focus for biomedical and agricultural research. The objective of this study was to map QTL in a large F2 (n = 1181) population resulting from an intercross between the M16 and ICR lines of mice. The M16 line, developed by long-term selection for 3- to 6-week weight gain, is larger, heavier, fatter, hyperphagic, and diabetic relative to its randomly selected control line of ICR origin. The F2 population was phenotyped for growth and energy intake at weekly intervals from 4 to 8 weeks of age and for body composition and plasma levels of insulin, leptin, TNFα, IL6, and glucose at 8 weeks and was genotyped for 80 microsatellite markers. Since the F2 was a cross between a selection line and its unselected control, the QTL identified likely represent genes that contributed to direct and correlated responses to long-term selection for rapid growth rate. Across all traits measured, 95 QTL were identified, likely representing 19 unique regions on 13 chromosomes. Four chromosomes (2, 6, 11, and 17) harbored loci contributing disproportionately to selection response. Several QTL demonstrating differential regulation of regional adipose deposition and age-dependent regulation of growth and energy consumption were identified.}, number={4}, journal={Genetics}, author={Allan, M. F. and Eisen, E. J. and Pomp, D.}, year={2005}, pages={1863–1877} } @book{eisen_2005, title={The mouse in animal genetics and breeding research}, ISBN={1860945651}, DOI={10.1142/9781860947162}, abstractNote={* The Beginnings: Ode to a Wee Mouse (E J Eisen) * Testing Quantitative Genetic Selection Theory (E J Eisen) * Maternal Effects, Genomic Imprinting and Evolution (J Funk-Keenan & W R Atchley) * Inbreeding and Crossbreeding (G A Brockmann) * Genotype by Environment Interaction: Lessons From the Mouse (W D Hohenboken) * Genetics of Growth in the Mouse (J M Cheverud) * Genetics of Body Composition and Metabolic Rate (L Bunger & W G Hill) * Genetics of Reproduction (M K Nielsen) * Genetics of Behavior (R J Hitzemann) * Genetics of Disease Resistance (S L Ewart & R A Ramadas) * Genomic Dissection of Complex Trait Predisposition (D Pomp) * Mouse Mutagenesis (D R Beier) * Embryo Biotechnologies (C A Pinkert & M J Martin) * Transgenics (J D Murray & E A Maga) * The Mouse in Biomedical Research (R B Roberts & D W Threadgill) * The Mouse Genome Sequencing Project: An Overview (M C Wendl et al.)}, publisher={London: Imperial College Press; Hackensack, NJ: World Scientific}, author={Eisen, E. J.}, year={2005} } @article{rocha_eisen_van vleck_pomp_2004, title={A large-sample QTL study in mice: I. Growth}, volume={15}, ISSN={["1432-1777"]}, DOI={10.1007/s00335-003-2312-x}, abstractNote={By use of long-term selection lines for high and low growth, a large-sample (n = approximately 1,000 F2) experiment was conducted in mice to further understand the genetic architecture of complex polygenic traits. In combination with previous work, we conclude that QTL analysis has reinforced classic polygenic paradigms put in place prior to molecular analysis. Composite interval mapping revealed large numbers of QTL for growth traits with an exponential distribution of magnitudes of effects and validated theoretical expectations regarding gene action. Of particular significance, large effects were detected on Chromosome (Chr) 2. Regions on Chrs 1, 3, 6, 10, 11, and 17 also harbor loci with significant contributions to phenotypic variation for growth. Despite the large sample size, average confidence intervals of approximately 20 cM exhibit the poor resolution for initial estimates of QTL location. Analysis with genome-wide and chromosomal polygenic models revealed that, under certain assumptions, large fractions of the genome may contribute little to phenotypic variation for growth. Only a few epistatic interactions among detected QTL, little statistical support for gender-specific QTL, and significant age effects on genetic architecture were other primary observations from this study.}, number={2}, journal={MAMMALIAN GENOME}, author={Rocha, JL and Eisen, EJ and Van Vleck, LD and Pomp, D}, year={2004}, month={Feb}, pages={83–99} } @article{rocha_eisen_van vleck_pomp_2004, title={A large-sample QTL study in mice: II. Body composition}, volume={15}, ISSN={["1432-1777"]}, DOI={10.1007/s00335-003-2308-6}, abstractNote={Using lines of mice having undergone long-term selection for high and low growth, a large-sample (n = ~1,000 F2) experiment was conducted to gain further understanding of the genetic architecture of complex polygenic traits. Composite interval mapping on data from male F2 mice (n = 552) detected 50 QTL on 15 chromosomes impacting weights of various organ and adipose subcomponents of growth, including heart, liver, kidney, spleen, testis, and subcutaneous and epididymal fat depots. Nearly all aggregate growth QTL could be interpreted in terms of the organ and fat subcomponents measured. More than 25% of QTL detected map to MMU2, accentuating the relevance of this chromosome to growth and fatness in the context of this cross. Regions of MMU7, 15, and 17 also emerged as important obesity "hot-spots." Average degrees of directional dominance are close to additivity, matching expectations for body composition traits. A strong QTL congruency is evident among heart, liver, kidney, and spleen weights. Liver and testis are organs whose genetic architectures are, respectively, most and least aligned with that for aggregate body weight. In this study, growth and body weight are interpreted in terms of organ subcomponents underlying the macro aggregate traits, and anchored on the corresponding genomic locations.}, number={2}, journal={MAMMALIAN GENOME}, author={Rocha, JL and Eisen, EJ and Van Vleck, LD and Pomp, D}, year={2004}, month={Feb}, pages={100–113} } @article{rocha_eisen_siewerdt_van vleck_pomp_2004, title={A large-sample QTL study in mice: III. Reproduction}, volume={15}, ISSN={["1432-1777"]}, DOI={10.1007/s00335-004-2364-6}, abstractNote={Using lines of mice having undergone long-term selection for high and low growth, a large-sample (n approximately to 1000 F2) experiment was conducted to gain further understanding of the genetic architecture of complex polygenic traits. Composite interval mapping on data from 10-week-old F2 females (n = 439) detected 15 quantitative trait loci (QTLs) on 5 chromosomes that influence reproduction traits characterized at day 16 of gestation. These QTL are broadly categorized into two groups: those where effects on the number of live fetuses (LF) were accompanied by parallel effects on the number of dead fetuses (DF), and those free of such undesirable effects. QTL for ovulation rate (OR) did not overlap with QTL for litter size, potentially indicating the importance of uterine capacity. Large dominance effects were identified for most QTL detected, and overdominance was also present. The QTL of largest effects were detected in regions of Chromosome 2, where large QTL effects for growth and fatness have also been found and where corroborating evidence from other studies exists. Considerable overlap between locations of QTL for reproductive traits and for growth traits corresponds well with the positive correlations usually observed among these sets of phenotypes. Some support for the relevance of QTL x genetic background interactions in reproduction was detected. Traits with low heritability demand considerably larger sample sizes to achieve effective power of QTL detection. This is unfortunate as traits with low heritability are among those that could most benefit from QTL-complemented breeding and selection strategies in food animal production.}, number={11}, journal={MAMMALIAN GENOME}, author={Rocha, JL and Eisen, EJ and Siewerdt, F and Van Vleck, LD and Pomp, D}, year={2004}, month={Nov}, pages={878–886} } @article{jerez-timaure_kearney_simpson_eisen_pomp_2004, title={Characterization of QTL with major effects on fatness and growth on mouse chromosome 2}, volume={12}, ISSN={["1071-7323"]}, DOI={10.1038/oby.2004.177}, abstractNote={AbstractObjective: To isolate and characterize a region on mouse chromosome 2 harboring quantitative trait loci with large influences on growth and fatness.Research Methods and Procedures: A congenic line [M16i.B6‐(D2Mit306‐D2Mit52); MB2] was created using the polygenic obese M16i selection line as the recipient for an ∼38‐centimorgan region from C57BL/6J. Males and females from M16i and MB2 were compared for body weight, body composition, feed consumption, and additional traits at 6, 15, and 24 weeks. Interactions of genotype and environment (low and high dietary fat) were investigated. Males (8 weeks) were evaluated for fatty acid profiles in liver and for transcriptional profiles in liver and adipose.Results: Consequences of replacing M16i alleles with C57BL/6J alleles in MB2 were maximized at 15 weeks. MB2 mice were up to 15% lighter than M16i at this age, with no differences in feed consumption. As a percentage of body weight, MB2 had dramatically less epididymal (males) or perimetrial (females) fat (1.17% vs. 2.79% pooled across sex) and lower total lipids (16.1% vs. 23.3%) than M16i. Decreased adiposity in MB2 was not dependent on gender or diet. MB2 mice also had significant decreases in levels of leptin, insulin, and glucose, decreased de novo synthesis of hepatic fatty acid, and transcriptional changes for many genes both within, and external to, the congenic region.Discussion: Results confirm the presence and large effects of mouse chromosome 2 quantitative trait loci and further define their phenotypic consequences related to energy balance. The MB2 congenic line is a powerful resource for eventual identification of pathways and mutations within genes regulating predisposition to growth and obesity.}, number={9}, journal={OBESITY RESEARCH}, author={Jerez-Timaure, NC and Kearney, F and Simpson, EB and Eisen, EJ and Pomp, D}, year={2004}, month={Sep}, pages={1408–1420} } @article{allan_eisen_pomp_2004, title={The M16 mouse: An outbred animal model of early onset polygenic obesity and diabesity}, volume={12}, ISSN={["1071-7323"]}, DOI={10.1038/oby.2004.176}, abstractNote={AbstractObjective: To characterize the phenotypic consequences of long‐term selective breeding for rapid weight gain, with an emphasis on obesity and obesity‐induced diabetes (diabesity).Research Methods and Procedures: M16 is the result of long‐term selection for 3‐ to 6‐week weight gain from an ICR base population. Experiment 1 characterized males from both lines for body weights (3, 6, and 8 weeks), feed (4 to 8 weeks) and H2O (6 to 8 weeks) consumption, and heat loss, body composition, and levels of several plasma proteins at 8 weeks of age. Experiment 2 characterized differences between lines for both sexes at three ages (6, 8, and 16 weeks) and fed two diets (high and normal fat). Body weight, composition, blood glucose, and plasma insulin and leptin levels were evaluated after an 8‐hour fast.Results: At all ages measured, M16 mice were heavier, fatter, hyperphagic, hyperinsulinemic, and hyperleptinemic relative to ICR. M16 males and females were hyperglycemic relative to ICR, with 56% and 22% higher fasted blood glucose levels at 8 weeks of age.Discussion: M16 mice represent an outbred animal model to facilitate gene discovery and pathway regulation controlling early onset polygenic obesity and type 2 diabetic phenotypes. Phenotypes prevalent in the M16 model, with obesity and diabesity exhibited at a young age, closely mirror current trends in human populations.}, number={9}, journal={OBESITY RESEARCH}, author={Allan, MF and Eisen, EJ and Pomp, D}, year={2004}, month={Sep}, pages={1397–1407} } @article{mahmoud_edens_eisen_havenstein_2004, title={The effect of dietary phosphorus on heat shock protein mRNAs during acute heat stress in male broiler chickens (Gallus gallus)}, volume={137}, ISSN={["1878-1659"]}, DOI={10.1016/j.cca.2003.10.013}, abstractNote={A 2 x 2 factorially arranged completely randomized experimental design was used to study the relationship between inorganic phosphorus (Pi) and heat shock protein (HSP) mRNA expression in different organs of commercial broiler cockerels during acute heat stress (HS). Brain, heart, liver and spleen were assayed for hsp70, hsp90alpha and hsp90beta mRNA. At 1 day of age, chickens were assigned randomly to two dietary Pi treatment groups (Pi-: 0.16%; Pi+: 0.5%). At 3 weeks of age, half of the chickens in each Pi group were subjected to HS (Ta=41 degrees C, 60 min) while the other half was maintained in a thermoneutral environment (CN, Ta=25 degrees C). The results showed inter-organ variation in the expression of HSP mRNAs. Brain expressed the most HSP mRNAs while spleen expressed the least. When broilers were subjected to HS, the expression of HSP mRNAs was influenced positively by the consumption of the Pi+ diet. However, analysis of variance revealed that Ta influenced HSP transcription more than phosphorus availability. Thermal stress caused induction of hsp90alpha and hsp90beta in heart, liver and spleen, but hsp90alpha and hsp9beta mRNA levels were stable in brain. Transcription of hsp70 increased (P< or =0.05) in all organs from chickens in HS groups when compared to chickens in CN groups. Although Pi+ did not show any significant increases in the expression of hsp mRNAs, there were consistently larger HSP mRNA values in liver and spleen tissues. The high expression of hsp90alpha and hsp90beta in brain of chicks in both CN and HS conditions could be due to the involvement of hsp90 in steroid hormone receptors or the high metabolic activity of neurons in the central nervous system.}, number={1}, journal={COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY}, author={Mahmoud, KZ and Edens, FW and Eisen, EJ and Havenstein, GB}, year={2004}, month={Jan}, pages={11–18} } @article{mahmoud_edens_eisen_havenstein_2004, title={Ascorbic acid decreases heat shock protein 70 and plasma corticosterone response in broilers (Gallus gallus domesticus) subjected to cyclic heat stress}, volume={137}, ISSN={["1096-4959"]}, DOI={10.1016/j.cbpc.2003.09.013}, abstractNote={It is known that ascorbic acid (AA) supplementation can ameliorate the chicken's responses to heat stress. The influence of AA on heart heat shock protein 70 (hsp70) and plasma corticosterone (CS) was evaluated in young male broiler chickens fed either no AA (N-AA) or 500 mg AA /kg (AA) and exposed to cyclic high temperatures (21 to 30 to 21 degrees C) over a 3.5 h period on three consecutive days. Dietary AA supplementation elevated plasma AA and maintained it at high levels after heating, but in N-AA birds, only heat elevated plasma AA. In N-AA fed chickens, plasma CS was elevated and was further increased by heat stress as compared with AA-fed birds. Heart hsp70 expression was greater in N-AA-fed chickens compared to AA-fed chickens, and heat stress further elevated hsp70 in both N-AA- and AA-fed birds. The hsp70 increase after heat was two-fold greater in N-AA- vs. AA-fed birds. Plasma CS and heart hsp70 were positively correlated, plasma AA and heart hsp70 were negatively correlated, and plasma CS and AA were negatively correlated. It was concluded that chickens experience a less severe stress response after exposure to high temperatures when they are provided dietary AA.}, number={1}, journal={COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY}, author={Mahmoud, KZ and Edens, FW and Eisen, EJ and Havenstein, GB}, year={2004}, month={Jan}, pages={35–42} } @article{fan_croom_eisen_spires_daniel_2003, title={Ionophores have limited effects on jejunal glucose absorption and energy metabolism in mice}, volume={81}, DOI={10.2527/2003.8182072x}, abstractNote={Two experiments, Trial 1 (in vitro) and Trial 2 (in vivo), were conducted to examine the effects of ionophores, monensin, laidlomycin, and laidlomycin propionate on whole-animal O2 consumption, organ weights, jejunal glucose absorption, and O2 utilization, as well as growth, feed and water consumption, and feed efficiency. In Trial 1, 30 male Swiss-Webster mice, 8 wk old, were used to measure the in vitro effects of each of the ionophores at concentrations of 1.62 or 16.2 mM. Six combinations of three ionophores at two concentrations resulted in a total of eight treatments. All eight treatments were exposed to jejunal rings from a single mouse for a total of 30 observations per treatment. Jejunal rings were exposed to each ionophore treatment for 15 min. Laidlomycin propionate (16.2 mM) decreased (P < 0.02) glucose absorption, as estimated by H3-3-O-methyl glucose uptake compared with all other treatments, whereas laidlomycin propionate (1.62 mM) increased (P = 0.032) jejunal DM content compared with 16.2 mM laidlomycin propionate. In Trial 2, 40 5-wk-old mice were allotted into four treatments--control and 16.2 mM each of monensin, laidlomycin, and laidlomycin propionate--for a total of 10 observations per treatment. Ionophores were administered via the drinking water for 14 d. No ionophore treatment had any effect on whole-mouse O2 consumption. Monensin increased (P = 0.004) stomach size and decreased (P = 0.049) the efficiency of BW gain compared with controls. Laidlomycin propionate decreased (P = 0.032) the percentage of whole jejunum oxygen consumption due to oubain-sensitive respiration compared with control. The efficiency of intestinal glucose absorption was not changed due to treatment in either trial. Under the conditions of these studies, monensin, laidlomycin, and laidlomycin propionate had minimal and inconsistent effects on jejunal function and energy utilization in mice. This investigation suggests that changes in the energetic requirements of animals treated with ionophores are not an issue in animal production.}, number={8}, journal={Journal of Animal Science}, author={Fan, Y. K. and Croom, J. and Eisen, E. J. and Spires, H. R. and Daniel, L. R.}, year={2003}, pages={2072–2079} } @article{leamy_pomp_eisen_cheverud_2002, title={Pleiotropy of quantitative trait loci for organ weights and limb bone lengths in mice}, volume={10}, DOI={10.1152/physiolgenomics.00018.2002.}, abstractNote={We investigated the genetic basis of several limb bone lengths and weights of organs in mice produced from a cross of the F1 between CAST/Ei (wild strain) and M16i (selected for rapid growth rate) back to M16i. From previous correlation studies, we hypothesized that quantitative trait loci (QTLs) would exhibit greater pleiotropy within than between the limb length and organ weight character sets. Using interval mapping procedures and significance testing at the chromosome-wise level, we discovered 14 putative QTLs affecting weight of the liver, spleen, heart, and/or kidney, 9 of which affected more than one organ; and 12 QTLs for limb lengths, all of which affected the length of two or more of the limb bones in these mice. As was hypothesized, most QTLs affected either organ weights or limb lengths independently of each other, although five QTLs were found that affected both sets of characters. The direction of the effect of these QTLs was almost always consistent within and between characters, with little evidence for antagonistic pleiotropy.}, number={1}, journal={Physiological Genomics}, author={Leamy, L. J. and Pomp, D. and Eisen, E. J. and Cheverud, J. M.}, year={2002}, pages={21–29} } @article{coles_croom_daniel_christensen_eisen_2001, title={In ovo peptide YY administration improves body weight at hatch and day 3 in turkey poults}, volume={10}, ISSN={["1056-6171"]}, DOI={10.1093/japr/10.4.380}, abstractNote={SUMMARY Previous studies in our laboratory have demonstrated that in ovo administration of peptide YY (PYY) at Day 18 of incubation enhanced adjusted feed conversion ratio (AFCR) and BW gains of broilers during the first week post-hatch. Preliminary studies have also shown that in ovo PYY administration at Day 25 of incubation also increases jejunal glucose absorption in 1-d-old Nicholas turkey poults. The objective of this study was to further elucidate the effects of in ovo PYY administration on growth and feed conversion in two turkey lines: a commercial growth line (BUT; British United Turkey, UK) and the Egg Line. Eggs from both turkey lines were randomly placed in the same incubator. On Day 25 of incubation, 380 BUT and 440 Egg Line eggs were injected with 100 µL 1.025% saline (control) or 600 µg PYY/kg egg weight. At hatch, 168 poults from each treatment group were wing-banded, weighed, and randomly distributed across pens in four Petersime batteries. A standard turkey starter crumble feed and water were available ad libitum. Feed and birds were weighed on Days 3, 10, and 17 to determine BW gains and AFCR. Poults of both lines from PYY-treated eggs were heavier (P < 0.01) than controls at Day 3. This effect was not apparent at Days 10 and 17. A subset of birds from each treatment group was randomly chosen at Day 17 and sexed by dissection. At hatch and again at Day 3, there were no BW differences (P = 0.94 and P = 0.15, respectively) noted between sexes. Males were heavier at 10 and 17 d (P = 0.0001). These results suggest that PYY enhances poult weight and may attenuate differences in BW caused by gender during early post-hatch life.}, number={4}, journal={JOURNAL OF APPLIED POULTRY RESEARCH}, author={Coles, BA and Croom, J and Daniel, LR and Christensen, VL and Eisen, EJ}, year={2001}, pages={380–384} } @article{bunger_laidlaw_bulfield_eisen_medrano_bradford_pirchner_renne_schlote_hill_2001, title={Inbred lines of mice derived from long-term growth selected lines: unique resources for mapping growth genes}, volume={12}, ISSN={["0938-8990"]}, DOI={10.1007/s00335001-3018-6}, abstractNote={Lines of mice selected for many generations for high or low growth in several laboratories around the world have been collected, and from these, inbred lines are being developed by recurrent full-sib mating in Edinburgh. There are seven high selected lines and four low lines (each low line is from the same base population as one of the high lines), and the histories of each are summarized. Mean body weight of males at 70 days of age in the Edinburgh laboratory in the heaviest inbred line (77 g) is 4.8-fold higher than in the lightest line (16 g), and 1.9-fold higher than in the least extreme high line (41 g). Litter size, food intake, and fat content also differ substantially. These inbred extreme selected lines are a uniquely valuable resource for QTL or gene mapping, candidate gene identification, and elucidation of epistatic effects.}, number={9}, journal={MAMMALIAN GENOME}, author={Bunger, L and Laidlaw, A and Bulfield, G and Eisen, EJ and Medrano, JF and Bradford, GE and Pirchner, F and Renne, U and Schlote, W and Hill, WG}, year={2001}, month={Sep}, pages={678–686} } @article{eisen_murray_2001, title={Segregation ratios and growth rate in inactive ovine metallothionein 1a-ovine growth hormone transgenic mice}, volume={79}, DOI={10.2527/2001.7971734x}, abstractNote={Objectives were to determine whether the oMt1a-oGH transgene shows normal Mendelian segregation and whether oMt1a-oGH mice exhibit normal growth without the zinc supplementation required to increase plasma oGH levels and stimulate growth. Transgenic mice were reciprocally backcrossed for four generations to high growth and control lines to form lines GM and GR, respectively. In the fifth generation, hemizygous transgenic mice (T/-) were crossed within each line. Pooled across backcross generations, there was a deficit (P < 0.001) of T/- progeny in lines GM (31.6%) and GR (22.2%) compared with expected (50%). In the T/- x T/- cross, the combined percentage of homozygous (T/T) and hemizygous transgenic mice was less (P < 0.001) than expected (75%) in both GM (44.2%) and GR (38.5%). Backcross T/- mice had lower (P < 0.05) 3-wk BW and lower (P < 0.001) 6-wk BW and 3- to 6-wk postweaning gains than nontransgenic mice. Similar genotypic differences were found in the T/- x T/- cross. No significant growth differences were found between T/T and T/- progeny. Using segregation ratios from the T/- x T/- mating, the relative fitness estimates of T/T, T/-, and -/- (nontransgenic) mice were 0.345, 0.223, and 1.0, respectively, in line GM and 0.218, 0.205, and 1.0 in line GR. Fitness estimates in the back-cross for T/- and -/- were 0.463 and 1.0 in line GM and 0.285 and 1.0 in line GR. Abnormal segregation ratios may be due to germline mosaicism or reduced fitness due to differential embryo survival. Reduced growth of oMt1a-oGH transgenic mice when the transgene is switched off suggests a subtle developmental abnormality, which may contribute to a reduction in fitness.}, number={7}, journal={Journal of Animal Science}, author={Eisen, E. J. and Murray, J. D.}, year={2001}, pages={1734–1741} } @article{siewerdt_eisen_murray_2000, title={Correlated changes in fertility and fitness traits in lines of oMt1a-oGH transgenic mice selected for increased 8-week body weight}, volume={117}, ISSN={["0931-2668"]}, DOI={10.1111/j.1439-0388.2000x.00208.x}, abstractNote={Correlated responses in fitness and fertility traits were compared in transgenic and nontransgenic lines of mice selected for increased 8‐week body weight. Two replicates of lines which either carried or did not carry the sheep metallothionein‐1a sheep growth hormone transgene (oMt1a‐oGH) were established. Host lines had been previously selected for rapid growth or selected randomly. Within‐litter selection was carried out for 13 generations, and a randomly selected control line was kept for each set of replicate lines. Mice were genotyped every generation for the presence of the transgene, but this information was not used in selection decisions. The oMt1a‐oGH construct was activated by adding 25 mm ZnSO4 to the drinking water from 3 weeks (weaning) until 8 weeks of age. Zinc stimulation of the transgene was not carried out during mating, gestation and lactation. Correlated responses in fitness traits were measured by regression of least‐squares means (as deviations from the control lines) on generation number. Two fitness indexes were defined to combine the information on individual fitness traits. The proportion of infertile matings was higher in generations 7 to 13 than in generations 0 to 6. Correlated responses to selection showed an increase in the cohabitation to littering interval in nontransgenic lines and an increase in litter sizes in lines from the selected background. Preweaning pup survival did not change over generations. Overall fitness increased in the transgenic line from the selection background whereas no changes were observed in the transgenic line from the control background. The initial frequency of 0.5 of the transgene was reduced to less than 0.10 in the selected background, but increased to an average of 0.62 in the control lines. The comparison of specific mating groups involving transgenic and nontransgenic mates revealed that the only consistent disadvantage in having a transgenic parent was the increase in the length of the cohabitation to littering interval. Major fitness problems were not associated with the oMt1a‐oGH transgene, which makes this construct a potential choice for use in livestock breeding programmes.}, number={2}, journal={JOURNAL OF ANIMAL BREEDING AND GENETICS-ZEITSCHRIFT FUR TIERZUCHTUNG UND ZUCHTUNGSBIOLOGIE}, author={Siewerdt, F and Eisen, EJ and Murray, JD}, year={2000}, month={Apr}, pages={83–95} } @article{parks_eisen_murray_2000, title={Correlated responses to selection for large body size in oMt1a-oGH mice: growth, feed efficiency and body composition}, volume={117}, ISSN={["1439-0388"]}, DOI={10.1046/j.1439-0388.2000.00253.x}, abstractNote={SummaryCorrelated responses were determined for growth, feed consumption, feed efficiency and body composition following short‐term selection for large 8‐week body weight in transgenic and nontransgenic mice. Replicate lines which either carried or did not carry the sheep metallothionein 1a‐sheep growth hormone transgene (oMt1a‐oGH) were established. The lines carrying the transgene at an initial frequency of 0.5 came from a high‐growth (TM) and a randomly selected (TC) background. The respective nontransgenic lines were identified as NM and NC. Control replicates (CC) came from the randomly selected background. During the selection process the transgene was activated by adding 25 mm ZnSO4 to the drinking water of all mice. Correlated responses were measured with (Z) and without (C) the addition of zinc. After seven and eight generations of selection, the frequency of transgenic mice in line TM had fallen sharply, whereas transgene frequency had risen moderately in TC. The reduced frequency of oMt1a‐oGH in the high‐growth genetic background may have been caused by a lower additive effect compared with the randomly selected background combined with a fitness disadvantage of the transgene. Therefore, the utility of a transgene in improving a quantitative trait may depend in part on genetic background. Correlated responses for most traits in NC were similar for Z and C. In contrast, correlated responses in TC showed marked differences in C compared with Z. For example, daily gain and feed efficiency showed no significantly correlated responses under C and positive responses (p < 0.001) under Z, and the reverse was found for indicators of body fat percentage. These line by environment (Z versus C) interactions may represent a genetic correlation of less than one between a trait expressed in two distinct environments. Thus, in developing lines with a transgene that can be regulated, a critical question is whether selection for quantitative trait(s) should be conducted when the transgene is activated or not activated.}, number={6}, journal={JOURNAL OF ANIMAL BREEDING AND GENETICS}, author={Parks, KR and Eisen, EJ and Murray, JD}, year={2000}, month={Dec}, pages={385–405} } @article{parks_eisen_murray_2000, title={Correlated responses to selection for large body size in oMt1a-oGH transgenic mice: organ traits}, volume={23}, ISSN={["1415-4757"]}, DOI={10.1590/S1415-47572000000400011}, abstractNote={The objective of the present study was to compare correlated responses in liver, spleen, kidney, heart and testis absolute weights and as a percentage of 8-week body weight following selection for large 8-week body weight in twice-replicated nontransgenic and transgene-carrier lines of mice from two genetic backgrounds. The transgene was an ovine metallothionein 1a-ovine growth hormone (oMt1a-oGH) construct, which was activated by adding 25 mM ZnSO4 to the drinking water. Lines NM and NC were nontransgenic lines derived from a high-growth and randomly selected background, respectively. Lines TM and TC were transgene-carrier lines formed from the respective genetic backgrounds. Line CC was a nontransgenic control from the randomly selected background. At weaning, male mice from each line were assigned to either zinc supplemented or control drinking water. Toe-clips were assayed by PCR for the presence or absence of the transgene. Correlated responses of absolute weights of all organs in nontransgenic lines indicated moderately high genetic correlations of organ weights with body weight, but on a percentage of body weight basis, the correlated responses were much lower. The correlated responses in visceral organ weights were lower in the presence of the inactivated oMt1a-oGH transgene than in its absence. The presence of the activated oMt1a-oGH combined with the effects of selection for growth increase had a greater impact on increasing the size of the splanchnic organs than did selection for large body weight in the absence of the transgene.}, number={4}, journal={GENETICS AND MOLECULAR BIOLOGY}, author={Parks, KR and Eisen, EJ and Murray, JD}, year={2000}, month={Dec}, pages={771–780} } @article{parks_eisen_parker_hester_murray_2000, title={Correlated responses to selection for large body size in oMt1a-oGH transgenic mice: reproductive traits}, volume={75}, ISSN={["0016-6723"]}, DOI={10.1017/S001667239900436X}, abstractNote={Correlated responses in female reproductive performance were evaluated following short-term selection within full-sib families for increased 8-week body weight in two replicates of four lines of mice: two ovine metallothionein–ovine growth hormone (oMt1a-oGH) transgene-carrier lines, one from a high-growth background (TM) and one from a control background (TC), and two non-transgenic lines, one from each of these genetic backgrounds (NM and NC, respectively). A fifth line (CC), not containing the transgene, served as a randomly selected control. The initial frequency of the oMt1a-oGH transgene construct in the TM and TC lines was 0·5. The frequency of transgenic females sampled at generations 7 and 8 of selection was 84·0% and 6·1% in the TC and TM lines, respectively. No significant female infertility differences were detected between transgene-carrier and non-transgenic lines or between transgenic and non-transgenic mice within carrier lines, whereas high-growth background lines had a higher infertility than control background lines (P < 0·05). Correlated responses in the TC transgene-carrier line were suggestive of reduced reproductive performance as indicated by increased post-implantation mortality (P < 0·05), number of dead fetuses plus implants (P < 0·05), and loss of fetuses from day 16 to parturition (P < 0·001). For the first two traits, the negative correlated responses were accounted for by the reduced performance of transgenic compared with non-transgenic females. Embryos carrying the transgene may also have a lower viability. In contrast, the NC non-transgenic line did not exhibit reduced reproductive performance for these traits. The low frequency of the transgene in the high-growth background TM line was associated with reduced fitness and a lower additive effect for 8-week body weight compared with the control background TC line.}, number={2}, journal={GENETICAL RESEARCH}, author={Parks, KR and Eisen, EJ and Parker, IJ and Hester, LG and Murray, JD}, year={2000}, month={Apr}, pages={199–208} } @article{berg_croom_fernandez_spears_eisen_taylor_daniel_coles_boeheim_mannon_2000, title={Peptide YY administration decreases brain aluminum in the Ts65Dn Down syndrome mouse model}, volume={64}, number={1-2}, journal={Growth, Development, & Aging}, author={Berg, B. M. and Croom, J. and Fernandez, J. M. and Spears, J. W. and Eisen, E. J. and Taylor, I. L. and Daniel, L. R. and Coles, B. A. and Boeheim, F. and Mannon, P. J.}, year={2000}, pages={3–19} } @article{leamy_pomp_eisen_cheverud_2000, title={Quantitative trait loci for directional but not fluctuating asymmetry of mandible characters in mice}, volume={76}, ISSN={["0016-6723"]}, DOI={10.1017/S0016672300004559}, abstractNote={Non-directional variation in right minus left differences in bilateral characters, referred to as fluctuating asymmetry (FA), often has been assumed to be largely or entirely environmental in origin. FA increasingly has been used as a measure of developmental stability, and its presumed environmental origin has facilitated the comparisons of populations believed to differ in their levels of stability. Directional asymmetry (DA), in which one side is consistently larger than the other, has been assumed to be at least partially heritable. Both these assumptions were tested with interval mapping techniques designed to detect any quantitative trait loci (QTLs) affecting FA or DA in 15 bilateral mandible characters in house mice resulting from a cross of the F1 between CAST/Ei (wild strain) and M16i (selected for rapid growth rate) back to M16i. For purposes of the analysis, all mandibles were triply measured and 92 microsatellite markers were scored in a total of 350 mice. No significant QTLs were found for FA, but three QTLs significantly affected DA in several characters, confirming both assumptions. The QTLs for DA were similar in location to those affecting the size of several of the mandible characters, although they accounted for an average of only 1% of the total phenotypic variation in DA.}, number={1}, journal={GENETICAL RESEARCH}, author={Leamy, LJ and Pomp, D and Eisen, EJ and Cheverud, JM}, year={2000}, month={Aug}, pages={27–40} } @article{siewerdt_eisen_murray_parker_2000, title={Response to 13 generations of selection for increased 8-week body weight in lines of mice carrying a sheep growth hormone-based transgene}, volume={78}, DOI={10.2527/2000.784832x}, abstractNote={The purpose of this study was to evaluate selection in lines of transgenic mice. Two replicates of lines that either carried or did not carry the sheep metallothionein-1a sheep growth hormone transgene (oMt1a-oGH) were established. The host lines had been previously selected for rapid growth or selected randomly. Within-litter selection for increased 8-wk body weight was carried out for 13 generations. The frequency of oMt1a-oGH was monitored in all generations in the transgenic lines, but no genotypic information regarding the transgene was used as an aid to selection. The oMt1a-oGH was activated from weaning, at 3 wk, until 8 wk of age by adding ZnSO4 to the drinking water. Zinc stimulation of the transgene was not done during mating, gestation, or lactation. Data on body weights and weight gains were analyzed with a conventional mixed model and with an animal model. Genetic progress was achieved in all lines subjected to directional selection. In the control background, response to selection for 8-wk body weight was larger in the nontransgenic lines than in the transgenic lines, whereas no difference was found in the selected background. The frequency of the transgene was increased from the initial .5 to .62 in the randomly selected background but decreased to .04 in lines from a selected background. The REML estimates of variance components and genetic gain estimates varied greatly between the two methods. In general, there was better agreement between the realized heritability estimates and the heritability estimates obtained from the conventional mixed model analysis than between realized heritability estimates and results obtained using the animal model. Favorable correlated responses were obtained for 3- and 6-wk body weights and on 3- to 6- and 6- to 8-wk weight gains. Correlated responses to selection were larger in the selected than in the nonselected background but were not affected by the presence of the transgene. Results suggest that constructs similar to the oMt1a-oGH, which allow tight regulation, may be successfully incorporated into commercial livestock and should have larger effects in populations that have not been subject to selection.}, number={4}, journal={Journal of Animal Science}, author={Siewerdt, F. and Eisen, E. J. and Murray, J. D. and Parker, I. J.}, year={2000}, pages={832–845} } @inbook{siewerdt_eisen_murray_1999, title={Direct and correlated responses to short-term selection for 8-week body weight in lines of transgenic (oMt1a-oGH) mice}, booktitle={Transgenic animals in agriculture}, publisher={New York: CABI Publishing}, author={Siewerdt, F. and Eisen, E. J. and Murray, J. D.}, editor={J. D. Murray, G. B. Anderson and A. M. Oberbauer and McGloughlin, M. M.Editors}, year={1999} } @article{alston-mills_parker_eisen_wilson_fletcher_1999, title={Factors influencing maternal behavior in the hubb/hubb mutant mouse}, volume={68}, ISSN={["0031-9384"]}, DOI={10.1016/S0031-9384(99)00149-3}, abstractNote={We examined the maternal behavior of hubb/hubb mutant mice and normal control (+/hubb) siblings. From previous observations we noted that mutants groom their pups less, suckle less than normal, and often cannibalize the young. To date, these observations had not been quantified. Although prolactin (PRL) is linked to maternal behavior, it was difficult to measure because of the hyperirratibility of the mutant mice. Consequently, dopamine (DA) and its metabolite, dihydroxyphenylacetic acid (DOPAC), were measured in the median eminence in brains of both normal and mutant mice. Tyrosine hydroxylase, the rate-determining step in dopamine synthesis, was localized in the brain by immunohistochemistry. Five mutant and nine normal dams were observed for pup retrieval and crouching. Mean time for pup retrieval was slower (p < 0.06) for mutants (28.09 s) than for normal dams (18.49 s). Crouching was the same for both strains. Mutant pups were cold to the touch, and not well groomed. Brains from both strains were examined at Day 11 and Day 18 of gestation and Day 2 and Day 11 of lactation. Qualitatively, tyrosine hydroxylase localization in the arcuate nucleus and median eminence was the same in both strains for the gestation samples. The decrease in staining observed from gestation to lactation in the normal mice was increased in the mutants. Dopamine was similar in both strains at all stages, but DOPAC was significantly higher at early lactation in the mutants. We do not assume an absolute inverse relationship between dopaminergic activities and prolactin, but it is likely that the increase in DOPAC in the mutant reflects a decrease in prolactin, which could contribute to the diminished maternal care in the mutants.}, number={1-2}, journal={PHYSIOLOGY & BEHAVIOR}, author={Alston-Mills, B and Parker, AC and Eisen, EJ and Wilson, R and Fletcher, S}, year={1999}, month={Dec}, pages={3–8} } @article{fan_croom_christensen_bird_daniel_mcbride_eisen_1998, title={Apparent energetic efficiency of jejunal glucose uptake in young adult turkeys selected for rapid growth}, volume={78}, ISSN={["0008-3984"]}, DOI={10.4141/A97-099}, abstractNote={ A rapid growth line (F) and a randombred control line (RBC2) of 16-wk-old unsexed turkeys were used to examine the effect of genetic selection for rapid growth on jejunal O2 consumption, glucose uptake and apparent energetic efficiency of glucose uptake. F line had 85% greater feed-deprived body weight (FBW, kilogram) than RBC2 line (P < 0.001) at 16 wk of age and a lighter (gram/kilogram FBW) and shorter (centimeter/kilogram FBW) small intestine and jejunum (P < 0.001). Additionally, the jejunum was composed of a higher proportion (P < 0.007) of mucosal tissue. There was no difference between the lines in apparent energetic efficiency (nmoles ATP expended/nmoles glucose uptake) of jejunal active glucose uptake. These data suggest selection for rapid growth in turkeys does not result in more efficient glucose uptake from the jejunum. Key words: Genetic selection, small intestine, glucose uptake, respiration, turkey }, number={3}, journal={CANADIAN JOURNAL OF ANIMAL SCIENCE}, author={Fan, YK and Croom, WJ and Christensen, VL and Bird, AR and Daniel, LR and McBride, BW and Eisen, EJ}, year={1998}, month={Sep}, pages={301–306} } @article{black_croom_eisen_petro_edwards_surwit_1998, title={Differential effects of fat and sucrose on body composition in A/J and C57BL/6 mice}, volume={47}, ISSN={["0026-0495"]}, DOI={10.1016/S0026-0495(98)90304-3}, abstractNote={The C57BL/6 (B6) mouse is more sensitive to the effects of a high-fat diet than the A/J strain. The B6 mouse develops severe obesity, hyperglycemia, and hyperinsulinemia when fed this dietary regimen. This study was conducted to determine the effects of dietary fat and sucrose concentrations on body composition and intestinal sucrase (EC 3.2.1.48) and maltase (EC 3.2.1.20) activity in these two mouse strains. High-fat diets, regardless of sucrose content, resulted in significant weight gain, higher body fat, and lower body protein and water content in both strains of mice. The shift toward higher body fat and lower protein and water content was far greater in the B6 strain. Low-fat, high-sucrose diets resulted in lower body weight in both strains, as well as significantly greater body protein content in B6 mice. Analysis of intestinal sucrase showed that the enzyme was less active in B6 mice when the diet was high in sucrose. Both sucrase and maltase had lower activity in the presence of high dietary fat in both mouse strains. The percent reduction of intestinal enzyme activity due to dietary fat was similar in both strains. The B6 mouse exhibits disproportionate weight gain and altered body composition on a high-fat diet. This coupled with the reduced body weight and increased body protein on a low-fat, high-sucrose diet suggests that factors-relative to fat metabolism rather than sucrose metabolism are responsible for obesity.}, number={11}, journal={METABOLISM-CLINICAL AND EXPERIMENTAL}, author={Black, BL and Croom, J and Eisen, EJ and Petro, AE and Edwards, CL and Surwit, RS}, year={1998}, month={Nov}, pages={1354–1359} } @article{eisen_peterson_parker_murray_1998, title={Effects of zinc ion concentration on growth, fat content and reproduction in oMT1a-oGH transgenic mice}, volume={62}, number={4}, journal={Growth, Development, & Aging}, author={Eisen, E. J. and Peterson, C. B. and Parker, I. J. and Murray, J. D.}, year={1998}, pages={173–186} } @article{siewerdt_eisen_conrad-brink_murray_1998, title={Gene action of the oMt1a-oGH transgene in two lines of mice with distinct selection backgrounds}, volume={115}, ISSN={["0931-2668"]}, DOI={10.1111/j.1439-0388.1998.tb00344.x}, abstractNote={SummaryTen transgenic (sheep metallothionein 1a‐sheep growth hormone transgene, oMt1a‐oGH) homozygous male mice were mated to females of two lines with distinct selection backgrounds. Inter se matings yielded F2 mice in each line: selected background and control background. Genotypes with respect to the transgene insert were obtained in all mice. Weekly body weights were taken. Males were dissected at 8 weeks of age and fat pads and organs were weighed. Females were mated at 10 weeks; reproductive data were collected on the 16th day after detection of a copulatory plug. Gene action on body, fat pads and organs weights showed dominance effects. The oMt1a‐oGH transgene caused body and organ weights to increase and fat pad weights to reduce. No unfavourable effects of the transgene insert were found on reproductive traits. Results indicate that incorporation of the oMt1a‐oGH in populations of mice should be successful.RésuméDix mâles souris, homozygotes pour le oMt1a‐oGH (mouton métallothionein 1a‐mouton hormone de croissance) ont été accouplés aux femelles de deus lignées avec différents fonds de sélection. Inter se accouplés ont rendu F2 souris dans chaque lignée: sélectionnée et contrôle. Les génotypes en ce qui concerne le transgène ont été mésurés dans tous les souris. Poids corporeles ont été obtenus chaque semaine. Les mâles ont été disséqués à huit semaines; dépôts adipaux et orgues ont été pesés. Les femelles ont été accouplés à dix semaines; données de reproduction ont été assemblés au seizième jour après la détéction d'un tampon de copulation. Dominance a été l'action génique sur le poids corporel, dépôts adipaux et orgues. Le transgène a augmenté les poids corporels et les poids des orgues mais il a réduit les poids des dépôts adipaux. Pas d'effects défavourables on été trouvés dans les caractères reproductives. Les résultats indiquent que l'incorporation du oMt1a‐oGH transgène dans populations de souris pourrai réussir.ZusammenfassungGenwirkung bei oMt1a‐oGH Transgenen in zwei Mäuselinien mit unterschiedlichem SelektionshintergrundZehn transgene (Schaf Metallothionein 1a‐Schaf Wachstumshormon, oMt1a‐oGH) homozypote Mäuseböcke wurde an Weibchen zweier Linien unterschiedlichen Selektionshintergrundes gepaart. Inter se Paarungen resultierten in F2 Mäusen mit Selektions bzw. Kontrollhintergrund. Alle Genotypen bezüglich des Transgeninserts wurden festgestellt. Gewichte wurden wöchentlich erhoben, Männchen im Alter von 8 Wochen seziert und Fettpolster unf Organgewichte bestimmt. Weibchen wurden im Alter von 10 Wochen gepaart und Reproduktionsdaten am 16. Tag nach Erscheinen des Kopulationspfropfen erhoben. Bei Körper‐, Fettpfropfen und Orangewichten zeigten sich Dominanzwirkungen. Das oMt1a‐oGH Transgen steigert Körper und Organgewichte und reduziert jenes des Fettpfropfens. Es zeigt keine ungünstigen Wirkungen auf Reproduktion, sodaß seine Einführung in Mäusepopulationen erfolgreich sein sollte.}, number={3}, journal={JOURNAL OF ANIMAL BREEDING AND GENETICS-ZEITSCHRIFT FUR TIERZUCHTUNG UND ZUCHTUNGSBIOLOGIE}, author={Siewerdt, F and Eisen, EJ and Conrad-Brink, JS and Murray, JD}, year={1998}, month={Jun}, pages={211–226} } @article{cefalu_croom_eisen_jones_daniel_taylor_1998, title={Jejunal function and plasma amino acid concentrations in the segmental trisomic Ts65Dn mouse}, volume={62}, number={1-2}, journal={Growth, Development, & Aging}, author={Cefalu, J. A. and Croom, W. J. and Eisen, E. J. and Jones, E. E. and Daniel, L. R. and Taylor, I. L.}, year={1998}, pages={47–59} } @article{benyon_eisen_jones_1997, title={Effects of canola oil based high fat diets on growth, fat deposition and serum triglyceride and cholesterol levels in lines of mice selected for high and low fat percentage}, volume={20}, DOI={10.1590/s0100-84551997000200009}, number={2}, journal={Revista Brasileira De Genetica}, author={Benyon, L. S. and Eisen, E. J and Jones, E. E.}, year={1997}, pages={203–213} } @article{fan_croom_christensen_black_bird_daniel_mcbride_eisen_1997, title={Jejunal glucose uptake and oxygen consumption in turkey poults selected for rapid growth}, volume={76}, ISSN={["0032-5791"]}, DOI={10.1093/ps/76.12.1738}, abstractNote={Two lines of turkey poults, one selected for rapid growth at 16 wk of age (F line) and the other a randombred control line (RBC2) were used to investigate the effect of selection for rapid growth on jejunal O2 consumption and glucose transport as well as whole-body O2 consumption. All trials used unsexed poults and were designed as a randomized complete block with day and line as independent variables. In Trial 1, 120 turkey poults, fed a standard starter ration (25.5% CP), were used to examine the effect of selection on feed intake, body weight gain, and efficiency from hatching (Day 0) to 13 d of age. At Day 14, 36 of 60 birds from each line were killed to measure intestinal length and weight and jejunal O2 consumption after 18 h of feed deprivation. Compared with the RBC2 line, the F line had relatively shorter but heavier small intestinal segments when adjusted by 18 h feed-deprived body weight (FBW; P < 0.001). The F line consumed more O2 over the entire jejunum adjusted to FBW than RBC2 line (43.8 vs 34.6 nmol O2/min.g FBW; P < 0.001). Jejunal ouabain- and cycloheximide-sensitive O2 consumption were greater (P < 0.05) in the F line. In Trial 2, 16 14-d-old poults from each line were used to measure in vitro jejunal glucose transport rate. There was no difference in glucose transport of the jejunum (nanomoles per minute per gram of FBW) between the lines. In Trial 3, 20 poults from each line were used to measure whole-body O2 consumption at 7 to 10 d of age. The F and RBC2 lines had similar whole-body O2 consumption rate per gram of FBW. These data suggest that selection of turkeys for rapid growth at 16 wk of age did not increase efficiency of jejunal glucose uptake in 14-d-old turkey poults.}, number={12}, journal={POULTRY SCIENCE}, author={Fan, YK and Croom, J and Christensen, VL and Black, BL and Bird, AR and Daniel, LR and McBride, BW and Eisen, EJ}, year={1997}, month={Dec}, pages={1738–1745} } @article{eisen_jones_rajendran_hall_1996, title={Effect of trimethylamine-carbomethoxyborane on growth traits and lipid metabolism in lines of mice selected for high and low fat content}, volume={60}, number={1}, journal={Growth (Menasha, Wis.)}, author={Eisen, E. J. and Jones, E. E. and Rajendran, K. G. and Hall, I. H.}, year={1996}, pages={7} } @article{eisen_murray_schmitt_1995, title={An ovine-growth-hormone transgene model suitable for selection experiments for growth in mice}, volume={112}, ISSN={["1439-0388"]}, DOI={10.1111/j.1439-0388.1995.tb00579.x}, abstractNote={SummaryBecause the oMT1a‐oGH transgene in mice can be regulated by dietary zinc, it provides a potential model for selection studies designed to increase growth rate. To determine the effect of oMT1a‐oGH on growth, fat content, and reproduction in the genetic background and environment in which selection would be conducted, males homozygous for the transgene were mated to females from high‐growth (M16) and control (ICR) lines to create hemizygous transgenics, TM and TC, respectively. Progeny either did (Z) or did not receive (C) 25 mm ZnSo4 from 3 (weaning) to 8 weeks. TM mice had larger (p < 0.001) weekly body weights than TC from 3 to 10 weeks, and Z mice were larger than C from 5 to 10 weeks in TC and from 6 to 10 weeks in TM. Significant (p < 0.01) line‐treatment interactions for weekly body weights from 4 to 8 weeks were caused by TC responding more to the transgene than TM mice. Compared to controls, male mice given zinc had reduced (p < 0.001) epididymal and subcutaneous fat‐pad weights as a percentage of body weight, but liver percentage was increased (p < 0.001). TC mice given zinc had reduced (p < 0.05) testis weights as a percentage of body weight, while there was no difference in TM mice. TM mice had larger liver (p < 0.01) and epididymal fat‐pad (p < 0.08) percentages than TC. Mating of Z females 2 weeks after discontinuation of zinc stimulation of transgene expression resulted in no significant differences between Z and C females in percentage infertile matings, days from exposure to a male to littering, and number of dead pups on day of birth; however, Z females had larger (p < 0.007) litters. This transgenic model is suitable for selection studies involving growth. When transgene expression is stimulated by exogenous zinc, growth rate is increased and there is no negative effect on female reproductive fitness when zinc supplement is discontinued.ZusammenfassungOvines Wachstumshormontransgen in Selektionsversuchen auf Mäusewachstum Nachdem das oMT1a‐oGH Transgen in Mäusen mittels Zinkgaben reguliert werden kann, bietet es ein interessantes Modell zur Untersuchung von Wachstumsselektionsversuchen. Um seine Wirkung auf Wachstum, Fettanteile, Fortpflanzung in verschiedenen genetische Milieu und verschiedenen Umwelten untersuchen zu können, wurden transgen homozygote Mäusemännchen an Weibchen einer wachstumsselektierten (M16) und einer Kontrollinie (ICR) zur Erzeugung von hemizygoten transgenischen TM‐, TC —Tieren gepaart. Nachkommen erhielten (Z) oder nicht (C) 25 mm ZnSO4 von 3 Wochen (absetzen) bis zum Alter von 8 Wochen. TM‐Mäuse hatten größere wöchentilche Zuwächse als die TC‐Mäuse von 3 bis 10 Wochen und Z‐Mäuse waren größer als C von 5 bis 10 Wochen in TC und von 6 bis 10 Wochen in TM. Signifikante Linien mal Behandlungsinteraktionen für wöchentliche Körpergewichte von 4 bis 8 Wochen waren darauf zurückzuführen, daß die TC mehr auf das Transgen angesprochen haben als TM. Im Vergleich zu Kontrollen haben Mäusemännchen nach Zinkgaben reduzierte Nebenhoden‐und subkutane Fettgewichte aber höheren Leberanteil. TC‐Mäuse mit Zink haben reduzierte Hodengewichte, wobei bei TM‐Mäusen kein Unterschied zu beobachten war. Diese hatten größere Leber‐und Nebenhodenfettgewichte als C. Paarung von Z‐Weibchen 2 Wochen nach Beendigung der Zinkgaben ergab keine signifikanten Unterschiede zwischen Z‐und C‐Weibchen im Hinblick auf Unfruchtbarkeit, Tage der Anwesenheit eines Männchens bis zum Wurf und Zahl toter Junger bei Geburt, aber Z‐Weibchen hatten größere Würfe. Dieses transgene Modell eignet sich zum Studium von Wachstumsselektion. Bei Stimulierung des Transgenes durch Zink wird Wachstumsrate gesteigert und es ergibt sich keine negative Wirkung auf weibliche Reproduktionsleistung, wenn Zinkgaben abgesetzt werden.}, number={5-6}, journal={JOURNAL OF ANIMAL BREEDING AND GENETICS}, author={Eisen, EJ and Murray, JD and Schmitt, TJ}, year={1995}, pages={401–413} } @article{eisen_benyon_douglas_1995, title={LONG-TERM RESTRICTED INDEX SELECTION IN MICE DESIGNED TO CHANGE FAT-CONTENT WITHOUT CHANGING BODY-SIZE}, volume={91}, ISSN={["0040-5752"]}, DOI={10.1007/bf00220897}, abstractNote={The objective of this study was to determine if low secondary selection differentials, caused by selecting within full-sib families, may have accounted for the failure of an intended restricted selection index to reduce epididymal fat pad weight (EF) without changing body weight (BW) in mice. Replicate lines that had been selected within full-sib families for high (HE) or low (LE) EF, while holding BW constant, were crossed. After two generations of random mating, two replicates were sampled and selection initiated for the same restricted index criteria except that mass selection was used to increase the selection differentials. In both phases of selection the HE restricted index selection, designed to increase EF without altering BW, was in agreement with expectation. In contrast, the LE index, designed to decrease EF without changing BW, did not agree with theory since BW increased while EF decreased only slightly. Therefore, reduced selection differentials could not explain the deviation from theory. A possible explanation may reside in the restricted selection index being more sensitive to changes in genetic parameters due to shifts in gene frequency as a consequence of the selection applied. However, linkage disequilibrium and genetic drift can not be ruled out as contributing factors to the asymmetry of response.}, number={2}, journal={THEORETICAL AND APPLIED GENETICS}, author={EISEN, EJ and BENYON, LS and DOUGLAS, JA}, year={1995}, month={Jul}, pages={340–345} } @article{eisen_fortman_chen_kopchick_1993, title={EFFECT OF GENETIC BACKGROUND ON GROWTH OF MICE HEMIZYGOTIC FOR WILD-TYPE OR DWARF MUTATED BOVINE GROWTH-HORMONE TRANSGENES}, volume={87}, ISSN={["0040-5752"]}, DOI={10.1007/bf00223760}, abstractNote={The effects of a high-growth genetic background on the growth of mice hemizygous for one of two growth hormone transgenes were examined. Male mice hemizygous for wild-type (W) and dwarf mutant (M) bovine growth hormone (bGH) transgenes were crossed with females of a high-growth selected (S) and control (C) line as follows: W x S, W x C, M x S and M x C. Body weights of progeny were recorded weekly from 2 to 10 weeks of age. F1 progeny were classified as carriers (P) or non-carriers (N) of the transgene by assaying tail DNA for bGH using the polymerase chain reaction and agarose gel electrophoresis. A deficiency in the number of f1 progeny carrying the W (P<0.05) and M (P<0.01) bGH transgene was most likely due to differential prenatal and early postnatal mortality. Bodyweight means of wild-type transgenic mice were larger (P < 0.05) than those of non-transgenic littermates by 3 weeks of age in a C background in contrast to 5 weeks in S. The wild-type bGH transgene increased adult body weights more in the C (155%) than in the S (136%) background, indicating transgene expression by selection background interaction (P < 0.05). However, the growth response to the wild-type transgene in the S background was still large. The dwarf mutant transgene had a greater effect on growth reduction in the S (70%) than in the C (84%) background, thus causing transgene expression by selection background interaction (P < 0.05). Gender by wild-type transgene effect interactions (P < 0.001) for adult body weight were caused by the transgene reducing the gender difference for body weight in C and eliminating it in S. The dwarf mutant caused a larger negative effect on growth in males than in females, resulting in a gender by dwarf mutant transgene interaction (P < 0.001) for adult body weights. Results indicate that the effect of a GH transgene on growth can be affected both by a high-growth genetic background and the gender of progeny.}, number={1-2}, journal={THEORETICAL AND APPLIED GENETICS}, author={EISEN, EJ and FORTMAN, M and CHEN, WY and KOPCHICK, JJ}, year={1993}, month={Oct}, pages={161–169} } @article{eisen_1993, title={MULTITRAIT RESTRICTED AND DESIRED GAINS SELECTION INDEXES DESIGNED TO CHANGE GROWTH AND BODY-COMPOSITION IN MICE}, volume={110}, ISSN={["0931-2668"]}, DOI={10.1111/j.1439-0388.1993.tb00713.x}, abstractNote={SummaryEffectiveness of restricted and desired gains index selection to change growth and body composition was tested in mice. Replicate lines were selected within full‐sib families as follows: RI, restricted index to increase 12‐week body weight (BW) and hind carcass weight (HC) with no change in right epididymal fat pad weight (EF); DG, desired gains index to increase BW and HC and decrease EF and right subcutaneous fat pad weight (SF) in designated proportions; RS, random selection. Realized heritabilities of index units, converted to an individual basis, were 0.65 ± 0.17 in RI and 0.50 ± 0.23 in DG, which exceeded the respective base population estimates of 0.32 ± 0.11 and 0.37 ±0.11, calculated as twice the regression of son on sire. Realized genetic correlation between the two selection index units of 0.87 ± 0.12 was not significantly different from the base population estimate of 0.91 ± 0.21. Realized correlated responses in component traits of the indices did not agree closely with expectation. Possible explanations for these discrepancies include genetic drift, weak selection intensity, discrepancies between estimated and true genetic parameters and changes in genetic parameters due to selection. Antagonistic selection for multiple traits may magnify the importance of these factors.ZusammenfassungRestringierte und erwünschte genetische Fortschritte zur Veränderung von Wachstum und Körperzusammensetzung von MäusenDie Wirksamkeit restraingierter und erwünschter Fortschritt‐Indexselektionsveränderung von Wachstum und Körpergewicht wurde bei Mäusen geprüft. Wiederholungslinien wurden innerhalb Vollgeschwisterfamilien folgendermaßen selektiert: RI, restringierter Index zur Steigerung des 12‐Wochengewichtes (BW), Schlachtkörperhälfte (HC) ohne Änderung des rechten Nebenhodenfettgewichts (EF); TG, erwünschter Zuchtfortschrittindex zur Steigerung von BW und HC und Verminderung von EF des rechten subkutanen Fettanteils (SF) in erwünschten Verhältnissen; RS Zufallsselektion. Realisierte Heritabilitätswerte im Index, auf individuelle Basis umgerechnet, waren 0,65 ±0,17 bei RI und 0,50 ± 0,23 bei DG, die die diesbezüglichen Basispopulationsschätzungen von 0,23 ±0,11 und 0,37 ±0,11 übertrafen. Diese wurden als die doppelte Regression von Sohn auf Vatertier berechnet. Realisierte genetische Korrelationen zwischen den zwei Selektionsindexeinheiten von 0,87 unterschieden sich nicht signifikant vom Basispopulationswert 0,91 ± 0,21. Realisierte korrelierte Selektion‐sreaktionen in den Teilmerkmalen der Indices haben mit den Erwartungswerten nicht gut übereingestimmt. Mögliche Erklärung für diese Abweichung beinhalten genetische Drift, schwache Selektionsintensität, Nichtübereinstimmung zwischen geschätzten und wahren genetischen Parametern und Veränderungen in diesen durch Selektion. Antagonistische Selektion für mehrere Merkmale könnte die Bedeutung dieser Faktoren steigern.}, number={1}, journal={JOURNAL OF ANIMAL BREEDING AND GENETICS-ZEITSCHRIFT FUR TIERZUCHTUNG UND ZUCHTUNGSBIOLOGIE}, author={EISEN, EJ}, year={1993}, month={Mar}, pages={13–29} } @article{eisen_1992, title={RESTRICTED SELECTION INDEX IN MICE DESIGNED TO CHANGE BODY-FAT WITHOUT CHANGING BODY-WEIGHT - CORRELATED RESPONSES}, volume={84}, ISSN={["0040-5752"]}, DOI={10.1007/bf00229488}, abstractNote={Correlated responses were studied in lines of mice selected for eight generations based on the criterion of a restricted selection index. Two replicate lines were selected in each treatment as follows: HE, high epididymal fat pad weight (EF) with zero change in body weight (BW) at 12 weeks of age; LE; low EF with zero change in BW; and RS, randomly. Correlated responses showed considerable variation between replicates, suggesting that genetic drift was important. Further, correlated responses for most traits were relatively small, probably because of low selection intensity. The HE line responded as expected in component traits of the restricted index. Associated compositional traits in HE responded as predicted since traits correlated with adiposity increased and hind carcass weight did not change significantly. Feed intake increased and feed efficiency (weight gain/feed intake) decreased in HE, as predicted. In contrast, the LE line did not respond in component traits as predicted since EF did not decrease and BW increased. Consequently, LE exhibited little change in traits associated with adiposity, but hind carcass weight, feed intake and feed efficiency increased. Of the correlated responses scored for fitness traits (littering rate, number of days from pairing of mate to littering, litter size and preweaning pup survival rate), significant effects were found for decreased littering rate in LE and increased prenatal survival rate in HE. In summary, correlated responses to restricted index selection generally agreed with expectation when responses in component traits of the index were considered.}, number={3-4}, journal={THEORETICAL AND APPLIED GENETICS}, author={EISEN, EJ}, year={1992}, month={Jul}, pages={307–312} } @article{eisen_1992, title={Restricted index selection in mice designed to change body fat without changing body weight: direct responses}, volume={83}, ISSN={["0040-5752"]}, DOI={10.1007/bf00232959}, abstractNote={Replicated within full-sib family restricted index selection was conducted for eight generations in mice for high or low epididymal fat pad weight (EF) holding body weight (BW) constant. Pooled realized heritability estimates of index units based on high, low and divergent selection were 0.42±0.20, 0.44±0.19 and 0.42± 0.05, respectively, which were not different from the base population estimate of 0.33±0.10. Realized responses per generation pooled across replicates in the high-fat restricted index lines were in the expected directions for EF (17.5±7.2 mg; P<0.05) and BW (0.03±0.58 g; P>0.05), but responses in the low-fat restricted index lines were discrepant for EF (0.3±5.1 mg; P>0.05) and BW (0.38±0.01 g; P<0.01). Consequently, the realized responses in component traits were decidedly asymmetric (P<0.05). A technique for estimating realized genetic parameters from index selection lines gave realized heritabilities for BW and EF of 0.68±0.04 and 0.45±0.05, respectively, and a realized genetic correlation between BW and EF of 0.93±0.01 compared with base population estimates of 0.43±0.08, 0.49±0.10 and 0.78±0.05, respectively. Possible explanations for the disparity between observed and expected responses in the low-fat restricted index lines include genetic drift, poor estimates of base population parameters, changes in genetic parameters with selection, linkage disequilibrium resulting from selection and asymmetric realized relative index weights.}, number={8}, journal={THEORETICAL AND APPLIED GENETICS}, author={Eisen, E. J.}, year={1992}, month={May}, pages={973–980} } @article{eisen_coffey_1990, title={Correlated responses in body composition based on selection for different indicator traits in mice}, volume={68}, DOI={10.2527/1990.68113557x}, abstractNote={Correlated responses in whole-body composition were determined in 12-wk-old male mice from replicate lines selected for 12 generations for high (HF) or low (LF) epididymal fat pad weight as a percentage of body weight (EPID) and high (HL) or low (LL) hind carcass weight as a percentage of body weight. The HF and LF lines diverged (P less than .01) in body fat percentage (FAT) and subcutaneous depot fat by 93 and 71%, respectively, of the control line (RC) mean. EPID increased (P less than .01) proportionately more than FAT in the HF line; EPID decreased (P less than .01) proportionately less than FAT in LF. Protein, fat and water as a percentage of empty body weight showed negative correlated responses (P less than .01) due to selection for EPID, but lean body mass, body weight and body length had positive correlated responses (P less than .01). Correlated responses of fat-free protein and ash percentage were minor. Correlated responses in HL and LL were the mirror images of those in HF and LF, but they generally were of smaller magnitude. The results indicate that, although there are high positive genetic correlations between fat depots in mice, local control of lipogenesis and(or) lipolysis exists at different sites of fat deposition. Further, the lack of correlated responses in fat-free percentage of protein (and percentage of ash) suggests that additive genetic variances are low for these traits and(or) the genetic correlations of these traits with the selection criteria are low.}, number={11}, journal={Journal of Animal Science}, author={Eisen, E. J. and Coffey, M. T.}, year={1990}, pages={3557} } @article{eisen_pomp_1990, title={Replicate differences in lines of mice selected for body composition}, volume={33}, DOI={10.1139/g90-045}, abstractNote={ Replicate differences were studied in lines of mice selected at 12 weeks of age for high (HF1, HF2) or low (LF1, LF2) right epididymal fat pad weight as a percentage of body weight (%EFP); for high (HL1, HL2) or low (LL1, LL2) hind carcass weight as a percentage of body weight (%HC); and randomly (RC1, RC2). Correlated traits were subcutaneous fat pad weight as a percentage of body weight (%SFP), water weight in hind carcass as a percentage of hind carcass weight (%WAT), body weights at 3, 6, and 12 weeks of age, and 3- to 6-week weight gain. Individual and maternal effects contributed to significant genetic drift for selected and correlated traits. No evidence indicated that drift was greater in selection treatments than in controls. Significant heterosis in replicate crosses within selection treatments was found for %HC in HL, LL, and LF and for %EFP in HF. Heterosis was insignificant in crosses of control replicates. Divergence in parental lines and replicate crosses was similar, indicating that differences in heterosis between high and low lines were small relative to divergence. Asymmetry tended to be greater between replicate crosses and parental lines, because selected replicates have greater average heterosis than control replicates. Multivariate discriminant function and Mahalanobis distance analysis of selected traits showed that divergence between replicates within selection treatments was much less than among selection treatments.Key words: selection, genetic drift, body composition, mice. }, number={2}, journal={Genome}, author={Eisen, E. J. and Pomp, D.}, year={1990}, pages={294} } @article{eisen_hauser_pomp_anderson_newbold_mccormick_1989, title={A RECESSIVE MUTATION CAUSING IMPERFORATE VAGINA IN MICE}, volume={80}, ISSN={["0022-1503"]}, DOI={10.1093/oxfordjournals.jhered.a110904}, abstractNote={A recessive mutation (ipv) causing imperforate vagina was discovered in a line of mice selected for low lean tissue mass as a proportion of body weight. Two full sisters were found to have marked swelling of the perineum and complete closure of the vagina. Crosses of heterozygotes identified by progeny testing produced a female progeny ratio not different from the 3 normal: 1 affected (chi 2 = 0.695; p less than .3) expected on the basis of a recessive allele at a single autosomal locus. As a consequence of the imperforate vagina, the uterus and vagina were greatly distended by fluid. The uterus of affected females displayed a swollen uterine lumen and thin endometrial stroma and muscularis. Ovarian tissue of affected females was similar to that of normal mice, and affected females produced ova that were normal in appearance. The mutation causing an imperforate vagina may present a useful model for studying the basis of abnormal vaginal development in other species and increasing the understanding of normal vaginal development in the mouse.}, number={6}, journal={JOURNAL OF HEREDITY}, author={EISEN, EJ and HAUSER, ME and POMP, D and ANDERSON, SG and NEWBOLD, RR and MCCORMICK, GY}, year={1989}, pages={478–482} } @article{eisen_1989, title={Genetic models to predict crossbred performance: A review}, volume={12}, number={3}, journal={Revista Brasileira De Genetica}, author={Eisen, E. J.}, year={1989}, pages={13} } @misc{eisen_1989, title={SELECTION EXPERIMENTS FOR BODY-COMPOSITION IN MICE AND RATS - A REVIEW}, volume={23}, ISSN={["0301-6226"]}, DOI={10.1016/0301-6226(89)90003-1}, abstractNote={Selection studies for body composition traits that used mice and rats as a model for livestock have been reviewed. Average realized heritability is higher for fat traits (0.49) than for lean traits (0.37), but there is considerable overlap. Selection for lean weight traits produced positive realized genetic correlations in growth, feed intake, gross feed efficiency and lean body mass, but body fat and protein percentages were not modified significantly at age of selection. Selection for fat percentage caused positive genetic correlations in growth, feed intake, feed efficiency and body fat, a negative response in body protein percentage and no response in lean body mass. An inexpensive and non-invasive method of measuring body composition is needed to improve the technical efficiency of selection. Future research should compare genetic variation in body composition at different ages. Desired gains and restricted selection index methods should be applied to modify body composition and growth. Hormones known to affect body composition and growth may be considered as additional selection criteria. Use of transgenic animals carrying genes coding for growth-promoting hormones, combined with artificial selection, offer additional strategies for changing body composition. Une revue bibliographique des expériences de sélection sur les caractères de composition corporelle utilisant la souris et le rat comme modèles pour les animaux domestiques a été effectuée. L'héritabilité réalisée des caractères se rapportant aux tissus gras (0,49) est plus élevée que pour les tissus maigres (0,37), mais il existe un chevauchement important. La sélection sur le poids de tissus maigres se traduit par des corrélations génétiques réalisées positives pour la croissance, la consommation d'aliment,l'efficacité alimentaire et la masse maigre de l'organisme, mais les pourcentages de graisses et de protéines corporelles ne sont pas significativement modifiés à l'âge à la sélection. La sélection sur le pourcentage de graisses entraîne des corrélations génétiques positives pour la croissance, la consommation,l'efficacité alimentaire et les graisses corporelles, une réponse négative pour le pourcentage de protéines corporelles et aucune réponse pour la masse maigre de l'organisme. Une méthode peu coûteuse et non invasive est nécessaire pour améliorer l'efficacité technique de la sélection. Les recherches futures devraient comparer les variations génétiques de la composition corporelle à différents âges. Les méthodes de sélection sur indice pour des gains désirés ou sur indice avec contrainte devraient être utilisées afin de modifier la composition corporelle et la croissance. Les hormones connues pour affecter la composition corporelle et la croissance pourraient être prises en compte en tant que critères de sélection supplémentaires. L'utilisation combinée d'animaux transgéniques porteurs de gènes codant pour les hormones qui stimulent la croissance et de la sélection artificielle permet d'autres stratégies pour modifier la composition corporelle. Studien, in denen auf Merkmale der Körperzusammensetzung selektiert wurde, wobei Ratten und Mäusen als Modelle für Nutztiere Verwendung fanden, werden rückblickend verglichen. Die mittlere realisierte Heretabilität liegt höher für Merkmale des Fettansatzes (0,37) als für Merkmale des Fleischansatzes (0,37); es gibt jedoch beachtliche Überschneidungen. Eine Selektion auf Fleischansatz führte zu positiven genetischen Korrelationen im Bezug auf das Wachstum, die Futteraufnahme, die Futterverwertung sowie die Masse des fettfreien Tierkörpers; Fett- und Proteinanteile am Tierkörper waren jedoch zum Selektionszeitpunkt nicht signifikant verändert. Eine Selektion auf hohen Fettanteil führte zu positiven genetischen Korrelationen im Bezug auf das Wachstum, die Futteraufnahme, die Futterverwertung und den Fettanteil am Tierkörper sowie zu einer negativen Antwort hinsichtlich des Proteinanteils; die Masse des mageren Tierkörpers blieb unbeeinfluβt. Man benötigt eine kostengünstige und nicht invasive Methode zur Untersuchung der Körperzusammensetzung, um die Wirksamkeit der Selektion verbessern zu können. Zukünftige Untersuchungen sollten die genetische Variation der Körperzusammensetzung in unterschiedlichen Altersstufen vergleichen. Die Methoden der Erfassung des Zuwachses und des Selektionsindexes mit Restriktionen sollten Verwendung finden, um Körperzusammensetzung und — wachstum zu modifizieren. Hormone, deren Wirkung auf Körperzusammensetzung und Wachstum bekannt ist, können als zusätzliche Selektionskriterien in Betracht kommen. Die Verwendung von transgenen Tieren, die für wachstumsfördernde Hormone kodierende Gene tragen, bietet sich — in Verbindung mit künstlicher Selektion — als weitere Strategie zur Beeinflussung der Körperzusammensetzung an.}, number={1-2}, journal={LIVESTOCK PRODUCTION SCIENCE}, author={EISEN, EJ}, year={1989}, month={Oct}, pages={17–32} } @article{eisen_prasetyo_1988, title={Estimates of genetic parameters and predicted selection responses for growth, fat and lean traits in mice}, volume={66}, DOI={10.2527/jas1988.6651153x}, abstractNote={Heritabilities (ĥ2) and genetic correlations (rG) were estimated by regression of offspring on sire in two replicate, unselected lines of mice. Traits were associated with growth, feed efficiency, fat deposition and lean tissue. The ĥ2 for growth traits ranged from .34 to .42, except for 3-wk body weight, which was only .05. The ĥ2 for feed efficiency was .28. Ranges in ĥ2 were .45 to .50 for fat deposition traits and .36 to .42 for lean tissue traits. The rG involving 3-wk to 6-wk feed efficiency with hind carcass and fat measurements at 12 wk were small. Antagonisms were found between the sign of rG and the direction of usual breeding goals for pairs of traits (e.g., rG greater than 0 between fat deposition and hind carcass weight and rG less than 0 between hind carcass as a percentage of body weight and body weight). Selection indexes were developed to counteract these antagonisms. Modified selection indexes were compared where responses in individual traits rather than the aggregate breeding value were of major importance. The aggregate breeding values and selection indexes included: 1) epididymal fat pad weight and body weight, 2) hind carcass weight and body weight, or 3) all three traits. Economic weights in retrospect were calculated for the modified selection indexes. In some cases, expected correlated responses in component traits were not influenced greatly over a wide range of ratios of economic weights, but in other cases the component traits changed sharply over a narrow range of ratios.}, number={5}, journal={Journal of Animal Science}, author={Eisen, E. J. and Prasetyo, H.}, year={1988}, pages={1153} } @article{eisen_bandy_1986, title={Prenatal and postnatal correlated responses in maternal traits of mice assessed by crossfostering}, volume={18}, DOI={10.1186/1297-9686-18-2-145}, abstractNote={A crossfostering design was used to estimate correlated responses in prenatal genetic and postnatal maternal effects for maternal traits of mice (female body weights at mating, at parturition and at 12-d postpartum, litter size and weight at birth, percent born alive, standardized (12 pups) 12-d litter weight and birth to 12-d litter feed efficiency = litter weight gain/dam feed intake).Lines of mice had been selected as follows : large first-parity litter size at birth (L+) ; large 6-wk body weight (W+) ; an index for large litter size and small 6-wk body weight (L+W-) and randomly (K).Prenatal line refers to the line into which a female was born, and postnatal line is that of the foster mother that nursed the female.Crossfostering sets were formed at birth with equal numbers of pups from the 4 lines reared either in litters of 8 or 16.Dams reared in litters of 8 were heavier, had larger litters at birth and larger litter weights at birth and 12-d postpartum (P < 0.05).No biologically important interactions were found between number reared and prenatal genetic effects or between number reared and postnatal maternal effects.Selection for litter size at birth and (or) 6-wk body weight resulted in large correlated responses in maternal traits.Correlated responses in postnatal maternal effects were relatively small compared with prenatal genetic effects.Prenatal genetic by postnatal maternal interactions generally were not of biological importance.Postnatal maternal effects contributed much less to correlated responses in traits associated with reproduction and maternal performance compared with growth-related traits.}, number={2}, journal={Genetics, Selection, Evolution}, author={Eisen, E. J. and Bandy, T. R.}, year={1986}, pages={145} } @article{eisen_saxton_1984, title={EFFECTS OF CONCURRENT LACTATION AND POSTPARTUM MATING ON REPRODUCTIVE-PERFORMANCE IN MICE SELECTED FOR LARGE LITTER SIZE}, volume={59}, ISSN={["0021-8812"]}, DOI={10.2527/jas1984.5951224x}, abstractNote={Reproductive and maternal performance of a line of mice selected for large first parity litter size (L+) and a control line (K) were compared under two mating systems: (1) postpartum mating (PP), in which females undergo concurrent gestation and lactation, and (2) postweaning mating (PW), in which females wean their litter before being remated. Females were evaluated in their first two parities. Litters in each line were standardized at birth to 4, 8, 12 or 16 pups in parity 1, and to 10 pups in parity 2. Concurrent gestation had no adverse effect on postnatal maternal performance in parity 1 of either line. In parity 2, both L+ and K declined in reproductive and postnatal maternal performance in PP compared with PW. The pattern of delayed implantation as number of pups nursed increased was similar in both lines under the PP regimen. Several interactions indicated that reproductive performance of L+ was more adversely affected than in K under postpartum mating. Pup mortality was greater in L+ than K under PP but not under PW. In the PP regimen, L+ dams nursing 12 and 16 pups had a lower mating success rate and dams nursing 16 pups had a smaller litter size and higher pup mortality than did K dams. Thus, when L+ dams nurse their natural litter, frequently exceeding 16 pups, their reproductive advantage over K dams observed in PW would be eliminated in PP. If the differences in the first two litters reflect subsequent parities, lifetime reproductive performance in the PP environment would be reduced in the high fecundity line. High fecundity appears to depend upon the environment of selection.}, number={5}, journal={JOURNAL OF ANIMAL SCIENCE}, author={EISEN, EJ and SAXTON, AM}, year={1984}, pages={1224–1238} } @article{eisen_bandy_mcclure_horstgenschwark_1984, title={ESTIMATING BODY-COMPOSITION IN MICE BY NEAR-INFRARED SPECTROPHOTOMETRY}, volume={58}, ISSN={["0021-8812"]}, DOI={10.2527/jas1984.5851181x}, abstractNote={Fat, protein and ash content of mice and other animal species are important response variables measured in genetic, nutritional and physiological studies. Procedures for estimating body composition usually include determination of fat by solvent extraction, N by the Kjeldahl method and ash by combustion. Near-infrared spectrophotometry (NIR) is a potentially rapid technique for estimating all three components simultaneously from a single instrument scan. One group of mice was used for calibration by relating the chemical determinations to optical variables of the wavelengths that provided the best fit for each component based on stepwise multiple linear regression. Independent variables were second derivatives of logarithms of reciprocals of reflectance for each wavelength. Coefficients of determination of calibration were .94, .91 and .64 for percentage of fat, protein and ash. Multiple regression procedures based on correlograms and characteristic spectra yielded comparable coefficients of determination. A nested sampling experiment provided estimates of percentage variation in each constituent associated with 1) individual mice, 2) sampling from total ground tissue, 3) packing of sample in the disk for reading and 4) instrument reading error. Respective percentages were 91.2, .3, 3.9 and 4.6 for fat; 94.4, .2, 2.6 and 2.8 for protein and 40.3, .0, .0 and 59.7 for ash. Repeatabilities based on NIR were .91, .94 and .40 for fat, protein and ash percentage, respectively. A second group of mice was used for evaluating the predictability of the calibration equations. Coefficients of determination of prediction were .92, .88 and .68 for fat, protein and ash percentage, respectively. Near-infrared spectrophotometry appears to be a useful technique for rapidly estimating fat and protein percentage in ground samples of mouse tissue and possibly other species, but seems less useful for predicting ash percentage.}, number={5}, journal={JOURNAL OF ANIMAL SCIENCE}, author={EISEN, EJ and BANDY, TR and MCCLURE, WF and HORSTGENSCHWARK, G}, year={1984}, pages={1181–1190} } @article{eisen_horstgenschwark_bandy_saxton_1984, title={POSTPARTUM PERFORMANCE IN A DIALLEL CROSS AMONG LINES OF MICE SELECTED FOR LITTER SIZE AND BODY-WEIGHT}, volume={58}, ISSN={["0021-8812"]}, DOI={10.2527/jas1984.584863x}, abstractNote={Postpartum dam performance was studied in a complete diallel design involving five lines of mice. The selection criterion in each line was: large litter size at birth (L+); large 6-wk body weight (W+); an index for large litter size and small 6-wk body weight (L+W-); the complementary index (L-W+) and random (K). Females from the five lines and 20 reciprocal F1 crosses were mated to sires of a randomly selected control line (CC). Correlated responses in average direct genetic and average maternal genetic effects for dam body weight and litter size at parturition persisted throughout lactation, indicating important pleiotropic effects. Major correlated responses occurred for litter weight, feed intake and litter feed efficiency, primarily due to average direct genetic effects. Using general combining ability and net line effects as criteria for choosing among lines, L+ had a distinct advantage if the objective was to increase litter size in a crossing program. If the objective was to maximize litter weaning weight, then W+ would be favored for net line effects, while L+ and W+ would be about equivalent for general combining ability. None of the lines had an advantage for litter feed efficiency. Direct heterosis for dam weight at 12 and 21 d of lactation averaged 2.7 and 1.9%, while for litter size the respective averages were 7.4 and 7.3%. The W+ X L+W- cross exhibited overdominance for litter size. Direct heterosis was moderate for feed intake and litter weight, but was negligible for litter feed efficiency because of the mathematical relationship among the three traits. Maternal heterosis for preweaning progeny growth was suppressed because of heterosis for litter size in the dam. Grand-maternal effects on growth of the young were small and would not be an important consideration in choosing among these lines in a crossbreeding program.}, number={4}, journal={JOURNAL OF ANIMAL SCIENCE}, author={EISEN, EJ and HORSTGENSCHWARK, G and BANDY, TR and SAXTON, AM}, year={1984}, pages={863–877} } @article{eisen_horstgenschwark_saxton_bandy_1983, title={GENETIC INTERPRETATION AND ANALYSIS OF DIALLEL CROSSES WITH ANIMALS}, volume={65}, ISSN={["1432-2242"]}, DOI={10.1007/bf00276256}, abstractNote={A genetic framework was developed for the interpretation of statistical parameters estimated from a diallel experiment among a fixed set of lines. These included average direct genetic, average maternal genetic, general combining ability, reciprocal, and line and specific direct and maternal heterotic effects. The genetic model is based on direct and maternal additive and dominance genetic effects as would be expected in animal species. The model assumes that dominance is the underlying basis of heterosis. As an example, litter size at birth was analyzed from a 5 × 5 diallel cross with mice.}, number={1}, journal={THEORETICAL AND APPLIED GENETICS}, author={EISEN, EJ and HORSTGENSCHWARK, G and SAXTON, AM and BANDY, TR}, year={1983}, pages={17–23} } @article{eisen_saxton_1983, title={GENOTYPE BY ENVIRONMENT INTERACTIONS AND GENETIC CORRELATIONS INVOLVING 2 ENVIRONMENTAL-FACTORS}, volume={67}, ISSN={["1432-2242"]}, DOI={10.1007/BF00303929}, abstractNote={The concept of the genetic correlation for one trait across environments was extended to two environmental factors B and C. Three additive genetic correlations for the same trait were defined: rG, across both environmental factors; rG(B), across C and within B; and rG(C), across B and within C. As genotype x environment variances increase, the genetic correlations across environments decrease. These three genetic correlations are biased downward in the presence of heterogeneity of genetic variances within environments when they are calculated from the usual analysis of variance (r*G, r*G(B), r*G(C)). Correction factors were derived to remove the bias. The two-way genotype by environment interaction variances can be biased upward or downward by the heterogeneity, but the three-way interaction variance is always biased upward. Correction factors for the interaction variances were also derived. Four additive genetic correlations between two traits (X and Y) were derived: rG xy, across both B and C; rG(B) xy, and rG(C) xy, across one environmental factor and within the other; and rG(BC) xy, within both B and C. These concepts were extended to genetic correlations for dominance and maternal effects. Paternal half-sib and factorial mating designs were used to obtain the various genetic correlations. An example of a paternal half-sib design with beef cattle was used to illustrate the methodology.}, number={1}, journal={THEORETICAL AND APPLIED GENETICS}, author={EISEN, EJ and SAXTON, AM}, year={1983}, pages={75–86} } @article{eisen_johnson_1981, title={Correlated responses in male reproductive traits in mice selected for litter size and body weight}, volume={99}, number={3}, journal={Genetics}, author={Eisen, E. J. and Johnson, B. H.}, year={1981}, pages={513} } @article{eisen_1981, title={Predicting selection response for total litter weight}, volume={98}, DOI={10.1111/j.1439-0388.1981.tb00329.x}, abstractNote={Zeitschrift für Tierzüchtung und ZüchtungsbiologieVolume 98, Issue 1-4 p. 55-76 Predicting selection response for total litter weight1 E.J. Eisen, Corresponding Author Institute of Animal Genetics, University of Edinburgh, Edinburgh, Scotland and Department of Animal Science, North Carolina State University, Raleigh, North Carolina, U.S.A. On leave at the Institute of Animal Genetics, West Mains Road, Edinburgh EH9 3JN, Scotland. Supported, in part, by an Underwood Fund Fellowship, Agricultural Research Council, and an Edinburgh University Biological Fellowship in the Department of Genetics.Department of Animal Science, North Carolina State University, Raleigh, North Carolina 27650, USASearch for more papers by this author E.J. Eisen, Corresponding Author Institute of Animal Genetics, University of Edinburgh, Edinburgh, Scotland and Department of Animal Science, North Carolina State University, Raleigh, North Carolina, U.S.A. On leave at the Institute of Animal Genetics, West Mains Road, Edinburgh EH9 3JN, Scotland. Supported, in part, by an Underwood Fund Fellowship, Agricultural Research Council, and an Edinburgh University Biological Fellowship in the Department of Genetics.Department of Animal Science, North Carolina State University, Raleigh, North Carolina 27650, USASearch for more papers by this author First published: January‐December 1981 https://doi.org/10.1111/j.1439-0388.1981.tb00329.xCitations: 8 1 Paper No. 6367 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Citing Literature Volume98, Issue1-4January‐December 1981Pages 55-76 RelatedInformation}, number={1}, journal={Journal of Animal Breeding and Genetics}, author={Eisen, E. J.}, year={1981}, pages={54} } @article{eisen_1980, title={Conclusions from long-term selection experiments with mice}, volume={97}, DOI={10.1111/j.1439-0388.1980.tb00937.x}, abstractNote={Zeitschrift für Tierzüchtung und ZüchtungsbiologieVolume 97, Issue 1-4 p. 305-319 Conclusions from long-term selection experiments with mice12 E. J. Eisen, Corresponding Author E. J. Eisen Department of Animal Science, North Carolina State University, Raleigh, N.C. USA and Institute of Animal Genetics, West Mains Road, Edinburgh, Scotland Supported, in part by an Underwood Fund Fellowship, Agricultural Research Council, and an Edinburgh University Biological Science Fellowship, Department of Genetics.Department of Animal Science. North Carolina State University, Raleigh, N.C. 27650, USASearch for more papers by this author E. J. Eisen, Corresponding Author E. J. Eisen Department of Animal Science, North Carolina State University, Raleigh, N.C. USA and Institute of Animal Genetics, West Mains Road, Edinburgh, Scotland Supported, in part by an Underwood Fund Fellowship, Agricultural Research Council, and an Edinburgh University Biological Science Fellowship, Department of Genetics.Department of Animal Science. North Carolina State University, Raleigh, N.C. 27650, USASearch for more papers by this author First published: January‐December 1980 https://doi.org/10.1111/j.1439-0388.1980.tb00937.xCitations: 26 1 Paper No. 636 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume97, Issue1-4January‐December 1980Pages 305-319 RelatedInformation}, number={4}, journal={Journal of Animal Breeding and Genetics}, author={Eisen, E. J.}, year={1980}, pages={305} } @article{eisen_nagai_bakker_hayes_1980, title={EFFECT OF LITTER SIZE AT BIRTH ON LACTATION IN MICE}, volume={50}, ISSN={["0021-8812"]}, DOI={10.2527/jas1980.504680x}, abstractNote={The relative influence of litter size at birth and dam body weight at parturition on lactational performance was determined with five among-line crossfostering experiments involving 17 populations of mice. Included were lines selected for postweaning growth and maternal performance, and unselected controls. Twelve-day litter weight of a crossfostered litter standardized to six or eight pups was used as the criterion of lactational performance. Litter size at birth had a small positive correlation with 12-day litter weight when pooled within lines in each crossfostering experiment (.06 to .30, with mean of .17). The correlation between dam body weight at parturition and her crossfostered 12-day litter weight was consistently higher (.13 to .51, with mean of .35). Litter size was positively correlated with dam body weight at parturition (.33 to .56, with mean of .47). The partial correlation between litter size and 12-day litter weight, with dam body weight at parturition held constant, was reduced (-.07 to .18, with mean of .02) compared to the simple correlation. Multiple regression analyses indicated that dam body weight at parturition consistently accounted for more of the variation in 12-day litter weight than litter size. The data provide no evidence to support the hypothesis that increased fetal number or mass results in a greater lactational output by the dam.}, number={4}, journal={JOURNAL OF ANIMAL SCIENCE}, author={EISEN, EJ and NAGAI, J and BAKKER, H and HAYES, JF}, year={1980}, pages={680–688} } @article{eisen_durrant_1980, title={EFFECTS OF MATERNAL ENVIRONMENT AND SELECTION FOR LITTER SIZE AND BODY-WEIGHT ON BIOMASS AND FEED-EFFICIENCY IN MICE}, volume={50}, ISSN={["0021-8812"]}, DOI={10.2527/jas1980.504664x}, abstractNote={Five lines of mice differing markedly in litter size at birth and 6-week body weight were compared at several ages for litter size, biomass (litter size × mean individual body weight) and feed efficiency (biomass gain/feed intake). The lines were selected as follows: large litter size (L+), large 6-week body weight (W+), selection index to decrease litter size and increase 6-week body weight (L-W+), selection index to increase litter size and decrease 6-week body weight (L+W-) and random selection (K). In Exp. 1, females of each line were reared in postnatal litter sizes (PLS) of N8, N12 or N16 to determine the importance of this maternal environment on their subsequent reproductive performance. In Exp. 2, L+ and W+ females were reared in litters of eight. Litter size differences among lines (L+ > [W+,L+W-] >K>L-W+) and among PLS ([N8, N121] > N16) established at birth were maintained through weaning. At 12 days and 3 and 6 weeks, biomass of W+ females exceeded that of L+ females, and both lines had greater biomass than the controls. The two index lines exhibited negative correlated responses in biomass. The observed correlated responses in biomass at 6 weeks were compared to predicted values based on direct and correlated responses observed for litter size and 6-week body weight in each line. Observed and predicted responses were in reasonable agreement. The L+ and W+ lines did not show any correlated response in litter feed efficiency from birth to 12 days, whereas the index lines exhibited negative correlated responses. From 12 days to weaning, the line rankings in litter feed efficiency were W+>L+>K>L-W+, while L+W- was not different from K. Litter feed efficiency from conception to weaning had similar positive correlated responses in the W+ and L+ lines, while no improvement was found in the L+W- and a decrease occurred in L-W+. There was no important effect of either PLS or line × PLS interaction on biomass and litter feed efficiency.}, number={4}, journal={JOURNAL OF ANIMAL SCIENCE}, author={EISEN, EJ and DURRANT, BS}, year={1980}, pages={664–679} } @article{eisen_durrant_1980, title={Effects of parity on reproductive performance in lines of mice selected for litter size or body weight}, volume={3}, number={1}, journal={Revista Brasileira De Genetica}, author={Eisen, E. J. and Durrant, B. S.}, year={1980}, pages={1} } @article{eisen_durrant_1980, title={GENETIC AND MATERNAL ENVIRONMENTAL-FACTORS INFLUENCING LITTER SIZE AND REPRODUCTIVE EFFICIENCY IN MICE}, volume={50}, ISSN={["0021-8812"]}, DOI={10.2527/jas1980.503428x}, abstractNote={Lines of mice which have been genetically differentiated in litter size at birth and 6-week body weight by single-trait or index selection were randomly assigned to be reared in postnatal litter sizes (PLS) of N8, N12 or N16. The lines were selected as follows: large litter size (L+), large 6-week body weight (W+), selection index to decrease litter size and increase 6-week body weight (L-W+), selection index to increase litter size and decrease 6-week weight (L+W-) and random selection (K). Line and PLS differences in female body weight at weaning and 6 weeks were significant (P less than .05), with W+ greater than L+ greater than L-W+ greater than K greater than L+W- and N8 greater than N12 greaater than N16. Although there was a significant interaction between line and PLS, ranking of the lines was the same at each PLS. Females of each line by PLS group were exposed to males of the same group. Line and PLS differences (P less than .05) in female body weight at copulatory plug, adjusted for age, exhibited the same rankings as the earlier weights. Litter size at birth (dead plus alive), number born alive and number born alive per female exposed each revealed similar differences (P less than .05) in the ranking of lines and PLS. No significant interactions were found. Means for litter size were as follows for each line: L+ (17.4) greater than [W+ (14.1), L+W- (14.3)] greater than K (12.0) greater than L-W+ (10.8), and for each PLS: [N8 (14.0), N12 (13.9)] greater than N16 (13.2). The decline in litter size as PLS increased did not differ significantly from linearity. Adjusting litter size for body weight at copulatory plug eliminated the significant effect of PLS [N8 (13.9), N12 (13.7), N16 (13.4)]. The established genetic differences in litter size among lines due to selection were considerably larger than the maternal environmental effect due to postnatal litter size. Because of the negligible interaction between line and PLS, valid inferences concerning genetic differences among lines in litter size may be made at any postnatal litter size between eight and 16.}, number={3}, journal={JOURNAL OF ANIMAL SCIENCE}, author={EISEN, EJ and DURRANT, BS}, year={1980}, pages={428–441} } @article{eisen_1980, title={INFLUENCE OF EARLY-PREGNANCY ON REPRODUCTIVE RATE IN LINES OF MICE SELECTED FOR LITTER SIZE}, volume={57}, ISSN={["0040-5752"]}, DOI={10.1007/bf00264673}, abstractNote={The influence of male-induced early puberty on female reproductive rate was determined in three lines of mice differing in litter size and body weight. The lines originated from a single base population and had undergone 20 generations of selection for the following criteria: large litter size at birth (L(+)), large litter size and small 6-week body weight (L(+)W(-)), or small litter size and large 6-week body weight (L(-)W(+)). Females were paired with a mature intact male of the same line at 3, 5 or 7 weeks of age. Mean mating age, averaged over lines, was 26.5 ± .3, 38.3 ± .3 and 52.7 ± .3 days. Exposure to a mature male accelerated female sexual maturation in each line. When contrasted with their sibs mated at a later age, early-pregnant females from each line exhibited a decline in one or more component of reproductive performance, suggesting that the physiological state of the very young female was not optimum for normal pregnancy. In comparisons of early and later mating ages, all three lines showed a decreased littering rate at first mating, number born alive, and individual birth weight of progeny adjusted for litter size; L(+) and L(+)W(-) mice showed an increased perinatal mortality rate; L(+) and L(-)W(+) had a reduction in litter size at birth. When the L(+), L(+)W(-) and L(-)W(+) lines were compared with an unselected strain and a line selected for high postweaning gain in similar experiments, a genotype by environment interaction was apparent since all lines did not respond in a similar manner to early mating. The line ranking for litter size at birth for each age at male-exposure was L(+)>L(+)W(-)>L(-)W(+), despite the significant line by age interaction. When litter size was adjusted by covariance for body weight at mating, the significant effects of age at male-exposure and line by age interaction were eliminated. All fertile females were remated after they had weaned their first litter to obtain information on litter size in parity two. Line differences in litter size at birth and number born alive were uniform across parities. An age by parity interaction was evident since the decreased fecundity at younger ages of male exposure in the L(+) and L(-)W(+) litters of parity one was not evident in parity two. Litter feed efficiency during first parity gestation was defined as litter birth weight divided by either cumulative feed intake of the dam from mating to parturition (GEI) or cumulative feed intake from weaning to parturition (GEII). The ranking of lines for GEI and GEH was L(+)> L(+)W(-)>L(-)W(+), but when feed efficiency was adjusted for littering rate, L(+)W(-) and L(-)W(+) were not significantly different. With regard to age at mating, the ranking for GEI (7 wk > 5 wk > 3 wk) was reversed from GEII (3 wk >5 wk > 7 wk) and these significant differences were maintained after adjustment for littering rate.}, number={5}, journal={THEORETICAL AND APPLIED GENETICS}, author={EISEN, EJ}, year={1980}, pages={209–220} } @article{eisen_leatherwood_1979, title={EFFECTS OF PREGNANCY AND MATING AGE ON PROTEIN AND FAT DEPOSITION IN POLYGENIC OBESE MICE}, volume={48}, ISSN={["1525-3163"]}, DOI={10.2527/jas1979.484810x}, abstractNote={Effects of pregnancy and mating age on rate (gain/day) and efficiency (gain/feed) of lean and fat deposition were determined in the M 16 line of mice selected for rapid postweaning weight gain. Correlated responses in M16 mice included increased lean and fat gain and efficiency. Exclusive of their litters, M 16 females had greater (P<.01) lean tissue growth and efficiency during pregnancy than M 16 virgin female contemporaries. Gain and efficiency of lean during pregnancy were higher (P<.01) in females mated at an early age (28.7+.5 days) than those mated at a normally later age (52.7_+.5 days). Pregnant females had decreased (P<.01) fat and energy retention and efficiency when compared with virgin controls of similar age. Early-pregnant females gained body fat and energy during pregnancy, whereas normalpregnant females showed a loss of body fat and energy. Total (female + litter) gain and efficiency of lean, fat and energy were higher (P<.01) in early-pregnant than normal-pregnant females. Total lean gain and efficiency were higher (P<.01) in gestating than virgin controls, but total fat and energy gain and efficiency were less (P<.01). During a 3-week postpartum test period, earlypregnant females did not differ from virgin controls in lean gain and efficiency, whereas normal-pregnant females were lower (P<.0 I) than virgin controls. Early-pregnant and normalpregnant females had higher (P<.01) fat and energy gain and efficiency than virgins during the 3-week postpartum period. (}, number={4}, journal={JOURNAL OF ANIMAL SCIENCE}, author={EISEN, EJ and LEATHERWOOD, JM}, year={1979}, pages={810–822} } @article{eisen_hayes_allen_bakker_nagai_1978, title={Cellular characteristics of gonadal fat pads, livers and kidneys in two strains of mice selected for rapid growth}, volume={42}, number={1}, journal={Growth (Menasha, Wis.)}, author={Eisen, E. J. and Hayes, J. F. and Allen, C. E. and Bakker, H. and Nagai, J.}, year={1978}, pages={7} } @article{eisen_1978, title={Single-trait and antagonistic index selection for litter size and body weight in mice}, volume={88}, number={4}, journal={Genetics}, author={Eisen, E. I.}, year={1978}, pages={781} } @article{eisen_bakker_nagai_1977, title={BODY-COMPOSITION AND ENERGETIC EFFICIENCY IN 2 LINES OF MICE SELECTED FOR RAPID GROWTH-RATE AND THEIR F1 CROSSES}, volume={49}, ISSN={["1432-2242"]}, DOI={10.1007/BF00304819}, abstractNote={Correlated responses to selection for increased growth rate were compared in two mouse populations (M16 and H6) of distinct genetic origin. Traits studied were body composition, feed intake, constituent gains and energetic efficiency. When compared with their respective controls (ICR and C2) at 6 and 9 weeks of age, body weight increased more in M16 (57%and 69 % of the control mean) than in H6 (40 % and 34%). The M16 showed correlated responses in fat percent of 2.6% (P <.05), 8.4% (P <.01) and 11.2% (P <.01) at 3, 6 and 9 weeks, respectively, whereas corresponding values in H6 were -2.4% (P <.05), 3.3% (P <.05) and 2.09 % (P >.05). The correlated responses in fat percent were 2.7 and 4.7 times higher in M16 than H6 at 6 and 9 weeks. The regression of ln fat weight on ln empty body weight was larger in M16 (P <.05) compared to ICR and larger (P <.01) in H6 compared to C2. Both M16 and H8 exhibited positive correlated responses from 3 to 6 weeks of age in feed intake and gain and efficiency in fat, protein, calories and ash; fat and caloric gain and efficiency exhibited higher correlated responses in M16 than H6. During the 6- to 9-week interval, the M16 population continued to evince positive correlated responses in gains and efficiencies of fat, protein and calories, whereas H6 did not. Several possible explanations are presented to account for the differences in correlated responses between the selected populations. Partitioning of correlated response differences between M16 and H6 into average direct and average maternal genetic effects indicated that average direct genetic effects, favoring M16, were responsible for the major difference between the selected populations. Direct heterosis in F1 crosses of the selected populations were generally not significant, although there was a tendency for fat percent and fat weight to show heterosis.}, number={1}, journal={THEORETICAL AND APPLIED GENETICS}, author={EISEN, EJ and BAKKER, H and NAGAI, J}, year={1977}, pages={21–34} } @article{eisen_bandy_1977, title={CORRELATED RESPONSES IN GROWTH AND BODY-COMPOSITION OF REPLICATED SINGLE-TRAIT AND INDEX SELECTED LINES OF MICE}, volume={49}, ISSN={["0040-5752"]}, DOI={10.1007/BF00281711}, abstractNote={Correlated responses in growth, body composition and efficiency were evaluated in lines of mice selected in the following ways: W(+)T i (o) , increased six-week body weight (WT6); W ° T i (+) , increased six-week tail length (TL6); W(+)T i (-) , increased WT6 and decreased TL6; W(-)T i (+) , decreased WT6 and increased TL6; M16, increased three-to six-week postweaning gain (PWG). Each of the first four selection treatments had two replicate lines (i = 1, 2) selected for 13 generations and the fifth treatment had one line selected for 30 generations. All lines were derived from a randombred ICR albino population which served as a control. Additional traits studied were three-week body weight and tail length, postweaning gain in tail length, percent body composition (ash, fat, moisture and protein) at six weeks of age, and three-to six-week feed consumption (CONS) and efficiency (EFF = PWG/CONS). Efficiency of body constituent gains (ash, fat, protein and caloric value) were determined by dividing each constituent by CONS. Relative to selection treatments, replicate variation in the array of traits was small and was primarily attributable to the effects of genetic drift; more frequent significant replicate differences among traits in W(+)T(-) were associated with a replicate difference in cumulative selection differentials. Selection for different criteria involving WT6 and TL6 did not change the allometric relationship between tail length and body weight in the three-to six-week age interval. The significant divergence between W(+)T ° and W °T(+) and between W(+)T(-) and W(-)T(+) was as expected for WT6 and TL6. Significant asymmetry of selection response between W(+)T(-) and W(-)T(+) for WT6 and TL6 was attributed to maternal effects. In agreement with theory, antagonistic index selection generally yielded smaller genetic responses than single trait selection. Positive correlated responses in CONS and EFF were found for M16 and W(+)T °. Significant correlated changes in CONS (positive in W °T(+) and negative in W(-)T(+)) were not accompanied by a significant change in EFF. In contrast, W(+)T(-) evinced an increased EFF and no change in CONS. Percent fat increased significantly in W(+)T ° and M16. For W(+)T(o), W(+)T(-) and M16, an increased energetic, fat and ash efficiency was observed, whereas M16 exhibited a positive increment in protein efficiency as well. Among selection treatment means, there were high positive correlations between WT6 and fat weight, protein weight, percent fat, CONS and EFF and a high negative correlation between WT6 and percent protein.}, number={3}, journal={THEORETICAL AND APPLIED GENETICS}, author={EISEN, EJ and BANDY, T}, year={1977}, pages={133–144} } @article{eisen_williams_hayes_1977, title={Effects of early pregnancy on postnatal maternal performance of mice}, volume={25}, DOI={10.1017/s0003356100038988}, abstractNote={SUMMARYThe influences of age at first pregnancy and number of suckling young on maternal performance of mice were studied. Mean mating ages for early-pregnant and normal-pregnant females were 27 and 52 days respectively. Litter size from parturition (day 0) to day 12 of lactation was standardized to either 8 or 12 pups. The more rapid (P<0·01) growth rate and feed conversion efficiency of early-pregnant dams from mating to parturition continued from 0 to 12 days of lactation but occurred primarily in the first 3 days of lactation, so that there were no differences in body weight or feed intake from days 3 to 12 of lactation. There were no age at pregnancy effects on total mammary gland DNA, RNA or RNA/DNA ratio at day 12 of lactation or on individual progeny weights or feed conversion efficiency of litter growth from 3 to 12 days of lactation. Dams suckling eight young had a lower (P<0·01) feed intake, gain and feed conversion efficiency from 0 to 3 days of lactation. From 0 to 12 days of lactation, these dams were smaller, consumed less feed and their individual progeny weights were larger (P<0·01). Dams suckling eight pups had smaller (P