@article{terajima_shibahara_nakano_kobayashi_godwin_nagaoka_watanabe_takada_mizukawa_2022, title={Age-related accumulation of persistent organic chemicals in captive king penguins (Aptenodytes patagonicus)}, volume={84}, ISSN={["1347-7439"]}, DOI={10.1292/jvms.22-0245}, abstractNote={Persistent organic chemicals are non-biodegradable in nature and have a tendency to bioaccumulate in the top organisms of the food chain. We measured persistent organic chemicals, including polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and benzotriazole-based ultraviolet stabilizers (UV-BTs), in the serum of captive king penguins (Aptenodytes patagonicus) using gas chromatography with an electron capture detector and mass spectrometry to examine their age-related accumulation. PCBs, DDE, UV-PS, and UV-9 were detected in the blood of captive king penguins, and the concentrations of total PCBs, DDE, and UV-9 were positively correlated with age. These results suggest that there is a similar age-related accumulation of persistent organic chemicals in marine birds in the wild, and that older individuals are at a higher risk of contamination.}, number={11}, journal={JOURNAL OF VETERINARY MEDICAL SCIENCE}, author={Terajima, Taiki and Shibahara, Anzu and Nakano, Yoshiaki and Kobayashi, Shohei and Godwin, John R. and Nagaoka, Kentaro and Watanabe, Gen and Takada, Hideshige and Mizukawa, Kaoruko}, year={2022}, month={Nov}, pages={1551–1555} }
 @article{lamm_lamb_klapheke_tyler_godwin_2022, title={Characterization and distribution of kisspeptins, kisspeptin receptors, GnIH, and GnRH1 in the brain of the protogynous bluehead wrasse (Thalassoma bifasciatum)}, volume={121}, ISSN={["1873-6300"]}, DOI={10.1016/j.jchemneu.2022.102087}, abstractNote={The kisspeptin and gonadotropin-inhibitory hormone (GnIH) systems regulate the hypothalamic-pituitary-gonadal (HPG) axis in a broad range of vertebrates through direct or indirect effects on hypothalamic/preoptic gonadotropin-releasing hormone (GnRH) neurons and pituitary gonadotropes. These systems are sensitive to environmental factors, including social conditions, and may assist in relaying environmental signals to the HPG axis in a potentially broad range of taxa. In this study, we characterized expression of kisspeptin-system genes (kiss1, kiss2, kissr1, and kissr2), gnih, and gnrh1 in the brain of the bluehead wrasse (Thalassoma bifasciatum), an important teleost model of socially-controlled sex change. We analyzed cDNA sequences and examined transcript distributions in the brain using in situ hybridization (ISH) to determine if expression occurs in reproductively-relevant and conserved regions. Expression of kiss1 was detected in the habenula, lateral hypothalamic nucleus (LHn), and preoptic area (POA), while kiss2 was expressed in the dorsal hypothalamus, with sporadic signal in the POA. Expression of kissr1 was detected in the POA, habenula, and LHn, while kissr2 expression was widespread. Gnih mRNA was detected in the posterior periventricular nucleus (NPPv), and gnrh1 neurons localized to the POA. Neurons expressing kissr2 and gnih co-regionalized in the NPPv, while kissr1, kissr2, and gnrh1 co-regionalized in the POA. Double-label ISH revealed very close proximity between kissr1 and gnrh1 neurons, suggesting potential communication between the kisspeptin and GnRH1 systems through these interneurons. These expression patterns are generally conserved and suggest that if kisspeptins do signal GnRH1 neurons, the interaction is indirect, possibly through neurons adjacent to GnRH1. With this foundation in place, future studies can help determine the interactions among these systems and whether these peptides assist in transducing social changes into a shift from female to male sexual function.}, journal={JOURNAL OF CHEMICAL NEUROANATOMY}, author={Lamm, Melissa S. and Lamb, April D. and Klapheke, Brandon P. and Tyler, William A. and Godwin, John R.}, year={2022}, month={Apr} }
 @article{gierus_birand_bunting_godahewa_piltz_oh_piaggio_threadgill_godwin_edwards_et al._2022, title={Leveraging a natural murine meiotic drive to suppress invasive populations}, volume={119}, ISSN={["1091-6490"]}, url={https://doi.org/10.1073/pnas.2213308119}, DOI={10.1073/pnas.2213308119}, abstractNote={
            Invasive rodents are a major cause of environmental damage and biodiversity loss, particularly on islands. Unlike insects, genetic biocontrol strategies including population-suppressing gene drives with biased inheritance have not been developed in mice. Here, we demonstrate a gene drive strategy (
            t
            CRISPR
            ) that leverages super-Mendelian transmission of the
            t
            haplotype to spread inactivating mutations in a haplosufficient female fertility gene (
            Prl
            ). Using spatially explicit individual-based in silico modeling, we show that
            t
            CRISPR
            can eradicate island populations under a range of realistic field-based parameter values. We also engineer transgenic
            t
            CRISPR
            mice that, crucially, exhibit biased transmission of the modified
            t
            haplotype and
            Prl
            mutations at levels our modeling predicts would be sufficient for eradication. This is an example of a feasible gene drive system for invasive alien rodent population control.
          }, number={46}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Gierus, Luke and Birand, Aysegul and Bunting, Mark D. and Godahewa, Gelshan I. and Piltz, Sandra G. and Oh, Kevin P. and Piaggio, Antoinette J. and Threadgill, David W. and Godwin, John and Edwards, Owain and et al.}, year={2022}, month={Nov} }
 @article{prim_phillips_lamm_brady_cabral_durden_dustin_hazellief_klapheke_lamb_et al._2021, title={Estrogenic signaling and sociosexual behavior in wild sex-changing bluehead wrasses, Thalassoma bifasciatum}, volume={11}, ISSN={["2471-5646"]}, DOI={10.1002/jez.2558}, abstractNote={Abstract}, journal={JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY}, author={Prim, Julianna H. and Phillips, Marshall C. and Lamm, Melissa S. and Brady, Jeannie and Cabral, Itze and Durden, Shelby and Dustin, Elizabeth and Hazellief, Allison and Klapheke, Brandon and Lamb, April D. and et al.}, year={2021}, month={Nov} }
 @article{oh_shiels_shiels_blondel_campbell_saah_lloyd_thomas_gould_abdo_et al._2021, title={Population genomics of invasive rodents on islands: Genetic consequences of colonization and prospects for localized synthetic gene drive}, volume={14}, ISSN={["1752-4571"]}, DOI={10.1111/eva.13210}, abstractNote={Abstract}, number={5}, journal={EVOLUTIONARY APPLICATIONS}, author={Oh, Kevin P. and Shiels, Aaron B. and Shiels, Laura and Blondel, Dimitri V and Campbell, Karl J. and Saah, J. Royden and Lloyd, Alun L. and Thomas, Paul Q. and Gould, Fred and Abdo, Zaid and et al.}, year={2021}, month={May}, pages={1421–1435} }
 @article{johnson_moore_wong_godwin_streelman_roberts_2020, title={Exploratory behaviour is associated with microhabitat and evolutionary radiation in Lake Malawi cichlids}, volume={160}, ISSN={["1095-8282"]}, DOI={10.1016/j.anbehav.2019.11.006}, abstractNote={Encountering and adaptively responding to unfamiliar or novel stimuli is a fundamental challenge facing animals and is linked to fitness. Behavioural responses to novel stimuli can differ strongly between closely related species; however, the ecological and evolutionary factors underlying these differences are not well understood, in part because most comparative investigations have focused on only two species. In this study, we investigate behavioural responses to novel environments, or exploratory behaviours, sampling from a total of 20 species in a previously untested vertebrate system, Lake Malawi cichlid fishes, which comprises hundreds of phenotypically diverse species that have diverged in the past one million years. We show generally conserved behavioural response patterns to different types of environmental stimuli in Lake Malawi cichlids, spanning multiple assays and paralleling other teleost and rodent lineages. Next, we demonstrate that more specific dimensions of exploratory behaviour vary strongly among Lake Malawi cichlids, and that a large proportion of this variation is explained by species differences. We further show that species differences in open field behaviours are explained by microhabitat and by a major evolutionary split between the mbuna and benthic/utaka radiations in Lake Malawi. Lastly, we track some individuals across a subset of behavioural assays and show that patterns of behavioural covariation across contexts are characteristic of modular complex traits. Taken together, our results tie ecology and evolution to natural behavioural variation, and highlight Lake Malawi cichlids as a powerful system for understanding the biological basis of exploratory behaviours.}, journal={ANIMAL BEHAVIOUR}, author={Johnson, Zachary V and Moore, Emily C. and Wong, Ryan Y. and Godwin, John R. and Streelman, Jeffrey T. and Roberts, Reade B.}, year={2020}, month={Feb}, pages={121–134} }
 @misc{price_windbichler_unckless_sutter_runge_ross_pomiankowski_nuckolls_montchamp-moreau_mideo_et al._2020, title={Resistance to natural and synthetic gene drive systems}, volume={33}, ISSN={["1420-9101"]}, DOI={10.1111/jeb.13693}, abstractNote={Abstract}, number={10}, journal={JOURNAL OF EVOLUTIONARY BIOLOGY}, author={Price, Tom A. R. and Windbichler, Nikolai and Unckless, Robert L. and Sutter, Andreas and Runge, Jan-Niklas and Ross, Perran A. and Pomiankowski, Andrew and Nuckolls, Nicole L. and Montchamp-Moreau, Catherine and Mideo, Nicole and et al.}, year={2020}, month={Oct}, pages={1345–1360} }
 @article{thomas_todd_muncaster_lokman_damsteegt_liu_soyano_gleonnec_lamm_godwin_et al._2019, title={Conservation and diversity in expression of candidate genes regulating socially-induced female-male sex change in wrasses}, volume={7}, ISSN={["2167-8359"]}, DOI={10.7717/peerj.7032}, abstractNote={Fishes exhibit remarkably diverse, and plastic, patterns of sexual development, most striking of which is sequential hermaphroditism, where individuals readily reverse sex in adulthood. How this stunning example of phenotypic plasticity is controlled at a genetic level remains poorly understood. Several genes have been implicated in regulating sex change, yet the degree to which a conserved genetic machinery orchestrates this process has not yet been addressed. Using captive and in-the-field social manipulations to initiate sex change, combined with a comparative qPCR approach, we compared expression patterns of four candidate regulatory genes among three species of wrasses (Labridae)—a large and diverse teleost family where female-to-male sex change is pervasive, socially-cued, and likely ancestral. Expression in brain and gonadal tissues were compared among the iconic tropical bluehead wrasse (Thalassoma bifasciatum) and the temperate spotty (Notolabrus celidotus) and kyusen (Parajulus poecilepterus) wrasses. In all three species, gonadal sex change was preceded by downregulation ofcyp19a1a(encoding gonadal aromatase that converts androgens to oestrogens) and accompanied by upregulation ofamh(encoding anti-müllerian hormone that primarily regulates male germ cell development), and these genes may act concurrently to orchestrate ovary-testis transformation. In the brain, our data argue against a role for brain aromatase (cyp19a1b) in initiating behavioural sex change, as its expression trailed behavioural changes. However, we find that isotocin (it, that regulates teleost socio-sexual behaviours) expression correlated with dominant male-specific behaviours in the bluehead wrasse, suggestingitupregulation mediates the rapid behavioural sex change characteristic of blueheads and other tropical wrasses. However,itexpression was not sex-biased in temperate spotty and kyusen wrasses, where sex change is more protracted and social groups may be less tightly-structured. Together, these findings suggest that while key components of the molecular machinery controlling gonadal sex change are phylogenetically conserved among wrasses, neural pathways governing behavioural sex change may be more variable.}, journal={PEERJ}, author={Thomas, Jodi T. and Todd, Erica V and Muncaster, Simon and Lokman, P. Mark and Damsteegt, Erin L. and Liu, Hui and Soyano, Kiyoshi and Gleonnec, Florence and Lamm, Melissa S. and Godwin, John R. and et al.}, year={2019}, month={Jun} }
 @article{manser_cornell_sutter_blondel_serr_godwin_price_2019, title={Controlling invasive rodents via synthetic gene drive and the role of polyandry}, volume={286}, ISSN={0962-8452 1471-2954}, url={http://dx.doi.org/10.1098/rspb.2019.0852}, DOI={10.1098/rspb.2019.0852}, abstractNote={
            House mice are a major ecosystem pest, particularly threatening island ecosystems as a non-native invasive species. Rapid advances in synthetic biology offer new avenues to control pest species for biodiversity conservation. Recently, a synthetic sperm-killing gene drive construct called
            t-Sry
            has been proposed as a means to eradicate target mouse populations owing to a lack of females. A factor that has received little attention in the discussion surrounding such drive applications is polyandry. Previous research has demonstrated that sperm-killing drivers are extremely damaging to a male’s sperm competitive ability. Here, we examine the importance of this effect on the
            t-Sry
            system using a theoretical model. We find that polyandry substantially hampers the spread of
            t-Sry
            such that release efforts have to be increased three- to sixfold for successful eradication. We discuss the implications of our finding for potential pest control programmes, the risk of drive spread beyond the target population, and the emergence of drive resistance. Our work highlights that a solid understanding of the forces that determine drive dynamics in a natural setting is key for successful drive application, and that exploring the natural diversity of gene drives may inform effective gene drive design.
          }, number={1909}, journal={Proceedings of the Royal Society B: Biological Sciences}, publisher={The Royal Society}, author={Manser, Andri and Cornell, Stephen J. and Sutter, Andreas and Blondel, Dimitri V. and Serr, Megan and Godwin, John and Price, Tom A. R.}, year={2019}, month={Aug}, pages={20190852} }
 @article{sudweeks_hollingsworth_blondel_campbell_dhole_eisemann_edwards_godwin_howald_oh_et al._2019, title={Locally Fixed Alleles: A method to localize gene drive to island populations}, volume={9}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-019-51994-0}, abstractNote={Abstract}, journal={SCIENTIFIC REPORTS}, author={Sudweeks, Jaye and Hollingsworth, Brandon and Blondel, Dimitri V and Campbell, Karl J. and Dhole, Sumit and Eisemann, John D. and Edwards, Owain and Godwin, John and Howald, Gregg R. and Oh, Kevin P. and et al.}, year={2019}, month={Nov} }
 @misc{sudweeks_hollingsworth_blondel_campbell_dhole_eisemann_edwards_godwin_howald_oh_et al._2019, title={Locally Fixed Alleles: A method to localize gene drive to island populations}, url={http://dx.doi.org/10.1101/509364}, DOI={10.1101/509364}, abstractNote={Abstract}, publisher={Cold Spring Harbor Laboratory}, author={Sudweeks, Jaye and Hollingsworth, Brandon and Blondel, Dimitri V. and Campbell, Karl J. and Dhole, Sumit and Eisemann, John D. and Edwards, Owain and Godwin, John and Howald, Gregg R. and Oh, Kevin and et al.}, year={2019}, month={Jan} }
 @article{godwin_serr_barnhill-dilling_blondel_brown_campbell_delborne_lloyd_oh_prowse_et al._2019, title={Rodent gene drives for conservation: opportunities and data needs}, volume={286}, ISSN={0962-8452 1471-2954}, url={http://dx.doi.org/10.1098/rspb.2019.1606}, DOI={10.1098/rspb.2019.1606}, abstractNote={
            Invasive rodents impact biodiversity, human health and food security worldwide. The biodiversity impacts are particularly significant on islands, which are the primary sites of vertebrate extinctions and where we are reaching the limits of current control technologies. Gene drives may represent an effective approach to this challenge, but knowledge gaps remain in a number of areas. This paper is focused on what is currently known about natural and developing synthetic gene drive systems in mice, some key areas where key knowledge gaps exist, findings in a variety of disciplines relevant to those gaps and a brief consideration of how engagement at the regulatory, stakeholder and community levels can accompany and contribute to this effort. Our primary species focus is the house mouse,
            Mus musculus
            , as a genetic model system that is also an important invasive pest. Our primary application focus is the development of gene drive systems intended to reduce reproduction and potentially eliminate invasive rodents from islands. Gene drive technologies in rodents have the potential to produce significant benefits for biodiversity conservation, human health and food security. A broad-based, multidisciplinary approach is necessary to assess this potential in a transparent, effective and responsible manner.
          }, number={1914}, journal={Proceedings of the Royal Society B: Biological Sciences}, publisher={The Royal Society}, author={Godwin, John and Serr, Megan and Barnhill-Dilling, S. Kathleen and Blondel, Dimitri V. and Brown, Peter R. and Campbell, Karl and Delborne, Jason and Lloyd, Alun L. and Oh, Kevin P. and Prowse, Thomas A. A. and et al.}, year={2019}, month={Nov}, pages={20191606} }
 @article{todd_ortega-recalde_liu_lamm_rutherford_cross_black_kardailsky_marshall graves_hore_et al._2019, title={Stress, novel sex genes, and epigenetic reprogramming orchestrate socially controlled sex change}, volume={5}, ISSN={2375-2548}, url={http://dx.doi.org/10.1126/sciadv.aaw7006}, DOI={10.1126/sciadv.aaw7006}, abstractNote={Ovary-to-testis transformation in a sex-changing fish involves transcriptomic and epigenomic reprogramming.}, number={7}, journal={Science Advances}, publisher={American Association for the Advancement of Science (AAAS)}, author={Todd, Erica V. and Ortega-Recalde, Oscar and Liu, Hui and Lamm, Melissa S. and Rutherford, Kim M. and Cross, Hugh and Black, Michael A. and Kardailsky, Olga and Marshall Graves, Jennifer A. and Hore, Timothy A. and et al.}, year={2019}, month={Jul}, pages={eaaw7006} }
 @article{barnhill-dilling_serr_blondel_godwin_2019, title={Sustainability as a Framework for Considering Gene Drive Mice for Invasive Rodent Eradication}, volume={11}, ISSN={2071-1050}, url={http://dx.doi.org/10.3390/su11051334}, DOI={10.3390/su11051334}, abstractNote={Gene drives represent a dynamic and controversial set of technologies with applications that range from mosquito control to the conservation of biological diversity on islands. Currently, gene drives are being developed in mice that may one day serve as an important tool for reducing invasive rodent pests, a key threat to island biodiversity and economies. Gene drives in mice are still in development in laboratories, and wild release of modified mice is likely a distant reality. However, technological changes outpace the existing capacity of regulatory frameworks, and thus require integrated governance frameworks. We suggest sustainability—which gives equal consideration to the environment, economy, and society—as one framework for addressing complexity and uncertainty in the governance of emerging gene drive technologies for invasive species management. We explore the impacts of rodent gene drives on island environments, including potential conservation and restoration of island biodiversity. We outline considerations for rodent gene drives on island economies, including impacts on agricultural and tourism losses, and reductions in biosecurity costs. Finally, we address the social dimension as an essential space for deliberation that will be integral to evaluating the potential deployment of gene drive rodents on islands.}, number={5}, journal={Sustainability}, publisher={MDPI AG}, author={Barnhill-Dilling, S. and Serr, Megan and Blondel, Dimitri and Godwin, John}, year={2019}, month={Mar}, pages={1334} }
 @inproceedings{campbell_saah_brown_godwin_gould_howald_piaggio_thomas_tompkins_threadgill_et al._2019, place={Gland, Switzerland}, title={Towards a genetic approach to invasive rodent eradications: Assessing reproductive competitiveness between wild and laboratory mice}, url={http://www.issg.org/pdf/publications/2019_Island_Invasives/PrintFiles/Serr.pdf}, DOI={10.2305/IUCN.CH.2019.SSC-OP.62.en}, abstractNote={The North American signal crayfish (Pacifastacus leniusculus) has been present in Scotland since at least 1995 and the species is now known to be present in a number of catchments. Once established, few opportunities for containment exist and eradication can often be impossible to achieve. However, in small, isolated water bodies, the application of a non-crayfish-specific biocide has provided the opportunity to remove this species permanently. In July 2011, signal crayfish were discovered in a flooded quarry pond at Ballachulish in the Scottish Highlands. This is an isolated site located ~100 km from the nearest known population and it is likely that the population was established as the result of a deliberate release of these animals 10 years previously. Experience gained from using the eradication technique at other sites in the UK led to the site being treated with a natural pyrethrum biocide (Pyblast®) in June 2012. Post treatment monitoring from 2012–2017 indicates that eradication has been successful. Monitoring of native species affected by the biocide suggests that both invertebrates and amphibians quickly recolonised the quarry pond. Eradication of crayfish using biocide is only feasible in water bodies where the entire population of crayfish can be exposed to a lethal dose and the impact on non-target species can be accepted. The technique is not appropriate for large, connected water bodies, although it may be possible to treat short stretches of canals where biocide exposure can be controlled and isolated populations of crayfish can be effectively treated.}, number={62}, booktitle={Island invasives: scaling up to meet the challenge}, publisher={IUCN}, author={Campbell, K.J. and Saah, J.R. and Brown, P.R. and Godwin, J. and Gould, F. and Howald, G.R. and Piaggio, A. and Thomas, P. and Tompkins, D.M. and Threadgill, D. and et al.}, editor={Veitch, C.R and Clout, MN and Martin, AR and Russell, JC and West, CJEditors}, year={2019}, pages={64–70} }
 @article{honeycutt_deck_miller_severance_atkins_luckenbach_buckel_daniels_rice_borski_et al._2019, title={Warmer waters masculinize wild populations of a fish with temperature-dependent sex determination}, volume={9}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/s41598-019-42944-x}, DOI={10.1038/s41598-019-42944-x}, abstractNote={Abstract}, number={1}, journal={Scientific Reports}, publisher={Springer Nature}, author={Honeycutt, J. L. and Deck, C. A. and Miller, S. C. and Severance, M. E. and Atkins, E. B. and Luckenbach, J. A. and Buckel, J. A. and Daniels, H. V. and Rice, J. A. and Borski, R. J. and et al.}, year={2019}, month={Apr} }
 @article{leitschuh_kanavy_backus_valdez_serr_pitts_threadgill_godwin_2017, title={Developing gene drive technologies to eradicate invasive rodents from islands}, volume={5}, ISSN={2329-9460 2329-9037}, url={http://dx.doi.org/10.1080/23299460.2017.1365232}, DOI={10.1080/23299460.2017.1365232}, abstractNote={Island ecosystems are highly threatened by invasive rats and mice. Currently, the only effective technology for eradicating rodents from islands is toxicants. Though effective, they are expensive a...}, number={sup1}, journal={Journal of Responsible Innovation}, publisher={Informa UK Limited}, author={Leitschuh, Caroline M. and Kanavy, Dona and Backus, Gregory A. and Valdez, Rene X. and Serr, Megan and Pitts, Elizabeth A. and Threadgill, David and Godwin, John}, year={2017}, month={Dec}, pages={S121–S138} }
 @article{todd_liu_lamm_thomas_rutherford_thompson_godwin_gemmell_2017, title={Female Mimicry by Sneaker Males Has a Transcriptomic Signature in Both the Brain and the Gonad in a Sex-Changing Fish}, volume={35}, ISSN={0737-4038 1537-1719}, url={http://dx.doi.org/10.1093/molbev/msx293}, DOI={10.1093/molbev/msx293}, abstractNote={Phenotypic plasticity represents an elegant adaptive response of individuals to a change in their environment. Bluehead wrasses (Thalassoma bifasciatum) exhibit astonishing sexual plasticity, including female-to-male sex change and discrete male morphs that differ strikingly in behavior, morphology, and gonadal investment. Using RNA-seq transcriptome profiling, we examined the genes and physiological pathways underlying flexible behavioral and gonadal differences among female, dominant (bourgeois) male, and female-mimic (sneaker) male blueheads. For the first time in any organism, we find that female mimicry by sneaker males has a transcriptional signature in both the brain and the gonad. Sneaker males shared striking similarity in neural gene expression with females, supporting the idea that males with alternative reproductive phenotypes have "female-like brains." Sneaker males also overexpressed neuroplasticity genes, suggesting that their opportunistic reproductive strategy requires a heightened capacity for neuroplasticity. Bourgeois males overexpressed genes associated with socio-sexual behaviors (e.g., isotocin), but also neuroprotective genes and biomarkers of oxidative stress and aging, indicating a hitherto unexplored cost to these males of attaining the reproductively privileged position at the top of the social hierarchy. Our novel comparison of testicular transcriptomes in a fish with male sexual polymorphism associates greater gonadal investment by sneaker males with overexpression of genes involved in cell proliferation and sperm quality control. We propose that morphological female-mimicry by sneaker male teleosts entails pervasive downregulation of androgenesis genes, consistent with low androgen production in males lacking well-developed secondary sexual characters.}, number={1}, journal={Molecular Biology and Evolution}, publisher={Oxford University Press (OUP)}, author={Todd, Erica V and Liu, Hui and Lamm, Melissa S and Thomas, Jodi T and Rutherford, Kim and Thompson, Kelly C and Godwin, John R and Gemmell, Neil J}, year={2017}, month={Nov}, pages={225–241} }
 @article{godwin_lamm_2017, title={Socially controlled sex change in fishes}, journal={Hormones, Brain and Behavior, vol 2: Non-Mammalian Hormone-Behavior Systems, 3rd edition}, author={Godwin, J. and Lamm, M.}, year={2017}, pages={31–46} }
 @article{kern_robinson_gass_godwin_langerhans_2016, title={Correlated evolution of personality, morphology and performance}, volume={117}, ISSN={["1095-8282"]}, DOI={10.1016/j.anbehav.2016.04.007}, abstractNote={Evolutionary change in one trait can elicit evolutionary changes in other traits due to genetic correlations. This constrains the independent evolution of traits and can lead to unpredicted ecological and evolutionary outcomes. Animals might frequently exhibit genetic associations among behavioural and morphological-physiological traits, because the physiological mechanisms behind animal personality can have broad multitrait effects and because many selective agents influence the evolution of multiple types of traits. However, we currently know little about genetic correlations between animal personalities and nonbehavioural traits. We tested for associations between personality, morphology and locomotor performance by comparing zebrafish (Danio rerio) collected from the wild and then selectively bred for either a proactive or reactive stress coping style ('bold' or 'shy' phenotypes). Based on adaptive hypotheses of correlational selection in the wild, we predicted that artificial selection for boldness would produce correlated evolutionary responses of larger caudal regions and higher fast-start escape performance (and the opposite for shyness). After four to seven generations, morphology and locomotor performance differed between personality lines: bold zebrafish exhibited a larger caudal region and higher fast-start performance than fish in the shy line, matching predictions. Individual-level phenotypic correlations suggested that pleiotropy or physical gene linkage likely explained the correlated response of locomotor performance, while the correlated response of body shape may have reflected linkage disequilibrium, which is breaking down each generation in the laboratory. Our results indicate that evolution of personality can result in concomitant changes in morphology and whole-organism performance, and vice versa.}, journal={ANIMAL BEHAVIOUR}, author={Kern, Elizabeth M. A. and Robinson, Detric and Gass, Erika and Godwin, John and Langerhans, R. Brian}, year={2016}, month={Jul}, pages={79–86} }
 @article{liu_todd_lokman_lamm_godwin_gemmell_2016, title={Sexual plasticity: A fishy tale}, volume={84}, ISSN={1040-452X}, url={http://dx.doi.org/10.1002/mrd.22691}, DOI={10.1002/mrd.22691}, abstractNote={SUMMARY}, number={2}, journal={Molecular Reproduction and Development}, publisher={Wiley}, author={Liu, Hui and Todd, Erica V. and Lokman, P. Mark and Lamm, Melissa S. and Godwin, John R. and Gemmell, Neil J.}, year={2016}, month={Sep}, pages={171–194} }
 @article{wong_lamm_godwin_2015, title={Characterizing the neurotranscriptomic states in alternative stress coping styles}, volume={16}, ISSN={["1471-2164"]}, url={https://doi.org/10.1186/s12864-015-1626-x}, DOI={10.1186/s12864-015-1626-x}, abstractNote={Animals experience stress in many contexts and often successfully cope. Individuals exhibiting the proactive versus reactive stress coping styles display qualitatively different behavioral and neuroendocrine responses to stressors. The predisposition to exhibiting a particular coping style is due to genetic and environmental factors. In this study we explore the neurotranscriptomic and gene network biases that are associated with differences between zebrafish (Danio rerio) lines selected for proactive and reactive coping styles and reared in a common garden environment.Using RNA-sequencing we quantified the basal transcriptomes from the brains of wild-derived zebrafish lines selectively bred to exhibit the proactive or reactive stress coping style. We identified 1953 genes that differed in baseline gene expression levels. Weighted gene coexpression network analyses identified one gene module associated with line differences. Together with our previous pharmacological experiment, we identified a core set of 62 genes associated with line differences. Gene ontology analyses reveal that many of these core genes are implicated in neurometabolism (e.g. organic acid biosynthetic and fatty acid metabolic processes).Our results show that proactive and reactive stress coping individuals display distinct basal neurotranscriptomic states. Differences in baseline expression of select genes or regulation of specific gene modules are linked to the magnitude of the behavioral response and the display of a coping style, respectively. Our results expand the molecular mechanisms of stress coping from one focused on the neurotransmitter systems to a more complex system that involves an organism's capability to handle neurometabolic loads and allows for comparisons with other animal taxa to uncover potential conserved mechanisms.}, journal={BMC Genomics}, author={Wong, R.Y. and Lamm, M.S. and Godwin, J.}, year={2015}, pages={425} }
 @article{liu_lamm_rutherford_black_godwin_gemmell_2015, title={Large-scale transcriptome sequencing reveals novel expression patterns for key sex-related genes in a sex-changing fish}, volume={6}, ISSN={2042-6410}, url={http://dx.doi.org/10.1186/s13293-015-0044-8}, DOI={10.1186/s13293-015-0044-8}, abstractNote={Teleost fishes exhibit remarkably diverse and plastic sexual developmental patterns. One of the most astonishing is the rapid socially controlled female-to-male (protogynous) sex change observed in bluehead wrasses (Thalassoma bifasciatum). Such functional sex change is widespread in marine fishes, including species of commercial importance, yet its underlying molecular basis remains poorly explored. RNA sequencing was performed to characterize the transcriptomic profiles and identify genes exhibiting sex-biased expression in the brain (forebrain and midbrain) and gonads of bluehead wrasses. Functional annotation and enrichment analysis were carried out for the sex-biased genes in the gonad to detect global differences in gene products and genetic pathways between males and females. Here we report the first transcriptomic analysis for a protogynous fish. Expression comparison between males and females reveals a large set of genes with sex-biased expression in the gonad, but relatively few such sex-biased genes in the brain. Functional annotation and enrichment analysis suggested that ovaries are mainly enriched for metabolic processes and testes for signal transduction, particularly receptors of neurotransmitters and steroid hormones. When compared to other species, many genes previously implicated in male sex determination and differentiation pathways showed conservation in their gonadal expression patterns in bluehead wrasses. However, some critical female-pathway genes (e.g., rspo1 and wnt4b) exhibited unanticipated expression patterns. In the brain, gene expression patterns suggest that local neurosteroid production and signaling likely contribute to the sex differences observed. Expression patterns of key sex-related genes suggest that sex-changing fish predominantly use an evolutionarily conserved genetic toolkit, but that subtle variability in the standard sex-determination regulatory network likely contributes to sexual plasticity in these fish. This study not only provides the first molecular data on a system ideally suited to explore the molecular basis of sexual plasticity and tissue re-engineering, but also sheds some light on the evolution of diverse sex determination and differentiation systems.}, number={1}, journal={Biology of Sex Differences}, publisher={Springer Science and Business Media LLC}, author={Liu, Hui and Lamm, Melissa S. and Rutherford, Kim and Black, Michael A. and Godwin, John R. and Gemmell, Neil J.}, year={2015}, month={Nov} }
 @article{wong_godwin_2015, title={Neurotranscriptome profiles of multiple zebrafish strains}, volume={5}, ISSN={["2213-5960"]}, DOI={10.1016/j.gdata.2015.06.004}, abstractNote={Behavioral displays or physiological responses are often influenced by intrinsic and extrinsic mechanisms in the context of the organism's evolutionary history. Understanding differences in transcriptome profiles can give insight into adaptive or pathological responses. We utilize high throughput sequencing (RNA-sequencing) to characterize the neurotranscriptome profiles in both males and females across four strains of zebrafish (Danio rerio). Strains varied by previously documented differences in stress and anxiety-like behavioral responses, and generations removed from wild-caught individuals. Here we describe detailed methodologies and quality controls in generating the raw RNA-sequencing reads that are publically available in NCBI's Gene Expression Omnibus database (GSE61108).}, journal={GENOMICS DATA}, author={Wong, Ryan Y. and Godwin, John}, year={2015}, month={Sep}, pages={206–209} }
 @article{lamm_liu_gemmell_godwin_2015, title={The Need for Speed: Neuroendocrine Regulation of Socially-controlled Sex Change}, volume={55}, ISSN={["1557-7023"]}, DOI={10.1093/icb/icv041}, abstractNote={Socially-controlled functional sex change in fishes is a dramatic example of adaptive reproductive plasticity. Functional gonadal sex change can occur within a week while behavioral sex change can begin within minutes. Significant progress has been made in understanding the neuroendocrine bases of this phenomenon at both the gonadal and the neurobiological levels, but a detailed mechanistic understanding remains elusive. We are working with sex-changing wrasses to identify evolutionarily-conserved neuroendocrine pathways underlying this reproductive adaptation. One key model is the bluehead wrasse (Thalassoma bifasciatum), in which sex change is well studied at the behavioral, ecological, and neuroendocrine levels. Bluehead wrasses show rapid increases in aggressive and courtship behaviors with sex change that do not depend on the presence of gonads. The display of male-typical behavior is correlated with the expression of arginine vasotocin, and experiments support a role for this neuropeptide. Estrogen synthesis is also critical in the process. Female bluehead wrasses have higher abundance of aromatase mRNA in the brain and gonads, and estrogen implants block behavioral sex change. While established methods have advanced our understanding of sex change, a full understanding will require new approaches and perspectives. First, contributions of other neuroendocrine systems should be better characterized, particularly glucocorticoid and thyroid signaling. Second, advances in genomics for non-traditional model species should allow conserved mechanisms to be identified with a key next-step being manipulative tests of these mechanisms. Finally, advances in genomics now also allow study of the role of epigenetic modifications and other regulatory mechanisms in the dramatic alterations across the sex-change process.}, number={2}, journal={INTEGRATIVE AND COMPARATIVE BIOLOGY}, author={Lamm, Melissa S. and Liu, Hui and Gemmell, Neil J. and Godwin, John R.}, year={2015}, month={Aug}, pages={307–322} }
 @article{campbell_beek_eason_glen_godwin_gould_holmes_howald_madden_ponder_et al._2015, title={The next generation of rodent eradications: Innovative technologies and tools to improve species specificity and increase their feasibility on islands}, volume={185}, ISSN={["1873-2917"]}, DOI={10.1016/j.biocon.2014.10.016}, abstractNote={Rodents remain one of the most widespread and damaging invasive alien species on islands globally. The current toolbox for insular rodent eradications is reliant on the application of sufficient anticoagulant toxicant into every potential rodent territory across an island. Despite significant advances in the use of these toxicants over recent decades, numerous situations remain where eradication is challenging or not yet feasible. These include islands with significant human populations, unreceptive stakeholder communities, co-occurrence of livestock and domestic animals, or vulnerability of native species. Developments in diverse branches of science, particularly the medical, pharmaceutical, invertebrate pest control, social science, technology and defense fields offer potential insights into the next generation of tools to eradicate rodents from islands. Horizon scanning is a structured process whereby current problems are assessed against potential future solutions. We undertook such an exercise to identify the most promising technologies, techniques and approaches that might be applied to rodent eradications from islands. We highlight a Rattus-specific toxicant, RNA interference as species-specific toxicants, rodenticide research, crab deterrent in baits, prophylactic treatment for protection of non-target species, transgenic rodents, virus vectored immunocontraception, drones, self-resetting traps and toxicant applicators, detection probability models and improved stakeholder community engagement methods. We present a brief description of each method, and discuss its application to rodent eradication on islands, knowledge gaps, challenges, whether it is incremental or transformative in nature and provide a potential timeline for availability. We outline how a combination of new tools may render previously intractable rodent eradication problems feasible.}, journal={BIOLOGICAL CONSERVATION}, author={Campbell, Karl J. and Beek, Joe and Eason, Charles T. and Glen, Alistair S. and Godwin, John and Gould, Fred and Holmes, Nick D. and Howald, Gregg R. and Madden, Francine M. and Ponder, Julia B. and et al.}, year={2015}, month={May}, pages={47–58} }
 @article{wong_mcleod_godwin_2014, title={Limited sex-biased neural gene expression patterns across strains in Zebrafish (Danio rerio)}, volume={15}, ISSN={["1471-2164"]}, DOI={10.1186/1471-2164-15-905}, abstractNote={Male and female vertebrates typically differ in a range of characteristics, from morphology to physiology to behavior, which are influenced by factors such as the social environment and the internal hormonal and genetic milieu. However, sex differences in gene expression profiles in the brains of vertebrates are only beginning to be understood. Fishes provide a unique complement to studies of sex differences in mammals and birds given that fish show extreme plasticity and lability of sexually dimorphic characters and behaviors during development and even adulthood. Hence, teleost models can give additional insight into sexual differentiation. The goal of this study is to identify neurotranscriptomic mechanisms for sex differences in the brain.In this study we examined whole-brain sex-biased gene expression through RNA-sequencing across four strains of zebrafish. We subsequently conducted systems level analyses by examining gene network dynamics between the sexes using weighted gene coexpression network analysis. Surprisingly, only 61 genes (approximately 0.4% of genes analyzed) showed a significant sex effect across all four strains, and 48 of these differences were male-biased. Several of these genes are associated with steroid hormone biosynthesis. Despite sex differences in a display of stress-related behaviors, basal transcript levels did not predict the intensity of the behavioral display. WGCNA revealed only one module that was significantly associated with sex. Intriguingly, comparing intermodule dynamics between the sexes revealed only moderate preservation. Further we identify sex-specific gene modules.Despite differences in morphology, physiology, and behavior, there is limited sex-biased neural gene expression in zebrafish. Further, genes found to be sex-biased are associated with hormone biosynthesis, suggesting that sex steroid hormones may be key contributors to sexual behavioral plasticity seen in teleosts. A possible mechanism is through regulating specific brain gene networks.}, journal={BMC GENOMICS}, author={Wong, Ryan Y. and McLeod, Melissa M. and Godwin, John}, year={2014}, month={Oct} }
 @article{wong_oxendine_godwin_2013, title={Behavioral and neurogenomic transcriptome changes in wild-derived zebrafish with fluoxetine treatment}, volume={14}, ISSN={["1471-2164"]}, DOI={10.1186/1471-2164-14-348}, abstractNote={Stress and anxiety-related behaviors are seen in many organisms. Studies have shown that in humans and other animals, treatment with selective serotonin reuptake inhibitors (e.g. fluoxetine) can reduce anxiety and anxiety-related behaviors. The efficacies and side effects, however, can vary between individuals. Fluoxetine can modulate anxiety in a stereospecific manner or with equal efficacy regardless of stereoisomer depending on the mechanism of action (e.g. serotonergic or GABAergic effects). Zebrafish are an emerging and valuable translational model for understanding human health related issues such as anxiety. In this study we present data showing the behavioral and whole brain transcriptome changes with fluoxetine treatment in wild-derived zebrafish and suggest additional molecular mechanisms of this widely-prescribed drug.We used automated behavioral analyses to assess the effects of racemic and stereoisomeric fluoxetine on male wild-derived zebrafish. Both racemic and the individual isomers of fluoxetine reduced anxiety-related behaviors relative to controls and we did not observe stereospecific fluoxetine effects. Using RNA-sequencing of the whole brain, we identified 411 genes showing differential expression with racemic fluoxetine treatment. Several neuropeptides (neuropeptide Y, isotocin, urocortin 3, prolactin) showed consistent expression patterns with the alleviation of stress and anxiety when anxiety-related behavior was reduced with fluoxetine treatment. With gene ontology and KEGG pathway analyses, we identified lipid and amino acid metabolic processes, and steroid biosynthesis among other terms to be over-enriched.Our results demonstrate that fluoxetine reduces anxiety-related behaviors in wild-derived zebrafish and alters their neurogenomic state. We identify two biological processes, lipid and amino acid metabolic synthesis that characterize differences in the fluoxetine treated fish. Fluoxetine may be acting on several different molecular pathways to reduce anxiety-related behaviors in wild-derived zebrafish. This study provides data that could help identify common molecular mechanisms of fluoxetine action across animal taxa.}, journal={BMC GENOMICS}, author={Wong, Ryan Y. and Oxendine, Sarah E. and Godwin, John}, year={2013}, month={May} }
 @article{marsh-hunkin_heinz_hawkins_godwin_2013, title={Estrogenic Control of Behavioral Sex Change in the Bluehead Wrasse, Thalassoma bifasciatum}, volume={53}, ISSN={1540-7063 1557-7023}, url={http://dx.doi.org/10.1093/icb/ict096}, DOI={10.1093/icb/ict096}, abstractNote={Estrogens activate male-typical sexual behavior in several mammalian and avian models. Estrogen signaling also appears critical in the control of sex change in some fishes, in which it is instead decreases in estradiol levels that may permit development of male-typical behaviors. The bluehead wrasse is a protogynous hermaphrodite that exhibits rapid increases in aggressive and male-typical courtship behavior as females undergo sex change. Removal of the ovaries does not prevent these changes. In two field experiments involving gonadally-intact and gonadectomized females, estradiol (E2) implants prevented behavioral sex change in large females who were made the largest members of their social groups through removals of more dominant fish. In contrast, cholesterol-implanted control females showed full behavioral sex change, along with a higher frequency both of aggressive interactions and of male-typical courtship displays than occurred in E2-implanted animals. To assess potential neural correlates of these behavioral effects of E2, we evaluated abundances of aromatase mRNA using in situ hybridization. Aromatase mRNA was more abundant in the POA of E2-implanted females than in cholesterol-implanted controls in gonadally-intact females. The lack of behavioral sex change coupled with increased levels of aromatase mRNA are consistent with an inhibitory role for E2, likely of neural origin, in regulating socially controlled sex change.}, number={6}, journal={Integrative and Comparative Biology}, publisher={Oxford University Press (OUP)}, author={Marsh-Hunkin, K. E. and Heinz, H. M. and Hawkins, M. B. and Godwin, J.}, year={2013}, month={Sep}, pages={951–959} }
 @article{scarlata_elias_godwin_powell_shepherdson_shipley_brown_2013, title={Influence of environmental conditions and facility on faecal glucocorticoid concentrations in captive pygmy rabbits (Brachylagus idahoensis)}, volume={22}, ISSN={["0962-7286"]}, DOI={10.7120/09627286.22.3.357}, abstractNote={Abstract}, number={3}, journal={ANIMAL WELFARE}, author={Scarlata, C. D. and Elias, B. A. and Godwin, J. R. and Powell, R. A. and Shepherdson, D. and Shipley, L. A. and Brown, J. L.}, year={2013}, month={Aug}, pages={357–368} }
 @article{mankiewicz_godwin_holler_turner_murashige_shamey_daniels_borski_2013, title={Masculinizing Effect of Background Color and Cortisol in a Flatfish with Environmental Sex-Determination}, volume={53}, ISSN={["1557-7023"]}, DOI={10.1093/icb/ict093}, abstractNote={Environmental sex-determination (ESD) is the phenomenon by which environmental factors regulate sex-determination, typically occurring during a critical period of early development. Southern flounder (Paralichthys lethostigma) exhibit temperature-dependent sex-determination that appears to be restricted to the presumed XX female genotype with the extremes of temperature, both high and low, skewing sex ratios toward males. In order to evaluate other environmental factors that may influence sex-determination, we investigated the influence of background color and cortisol on sex-determination in southern flounder. Experiments involving three sets of tanks, each painted a different color, were conducted at different temperatures using southern flounder of mixed XX-XY genotype. The studies involved rearing juvenile southern flounder in either black, gray, or blue tanks and sex-determination was assessed by gonadal histology. In both studies, blue tanks showed significant male-biased sex ratios (95 and 75% male) compared with black and gray tanks. The stress corticosteroid cortisol may mediate sex-determining processes associated with environmental variables. Cortisol from the whole body was measured throughout the second experiment and fishes in blue tanks had higher levels of cortisol during the period of sex-determination. These data suggest that background color can be a cue for ESD, with blue acting as a stressor during the period of sex-determination, and ultimately producing male-skewed populations. In a separate study using XX populations of southern flounder, cortisol was applied at 0, 100, or 300 mg/kg of gelatin-coated feed. Fish were fed intermittently prior to, and just through, the period of sex-determination. Levels of gonadal P450 aromatase (cyp19a1) and forkhead transcription factor L2 (FoxL2) messenger RNA (mRNA) were measured by qRT-PCR as markers for differentiation into females. Müllerian-inhibiting substance mRNA was used as a marker of males' gonadal development. Control fish showed female-biased sex ratios approaching 100%, whereas treatment with 100 mg/kg cortisol produced 28.57% females and treatment with 300 mg/kg cortisol produced only 13.33% females. These results suggest that cortisol is a critical mediator of sex-determination in southern flounder by promoting masculinization. This linkage between the endocrine stress axis and conserved sex-determination pathways may provide a mechanism for adaptive modification of sex ratio in a spatially and temporally variable environment.}, number={4}, journal={INTEGRATIVE AND COMPARATIVE BIOLOGY}, publisher={Oxford University Press}, author={Mankiewicz, Jamie L. and Godwin, John and Holler, Brittany L. and Turner, Poem M. and Murashige, Ryan and Shamey, Renzo and Daniels, Harry V. and Borski, Russell J.}, year={2013}, month={Oct}, pages={755–765} }
 @inbook{godwin_sawyer_perrin_oxendine_kezios_2012, title={Adapting the Open Field Test to Assess Anxiety-Related Behavior in Zebrafish}, ISBN={9781617795961 9781617795978}, ISSN={0893-2336 1940-6045}, url={http://dx.doi.org/10.1007/978-1-61779-597-8_13}, DOI={10.1007/978-1-61779-597-8_13}, abstractNote={The open field test is a well-established paradigm for assaying anxiety-related behaviors and has been successfully employed in a broad range of species. We describe an adaptation of this test for the zebrafish, which is increasingly widely used as a model for anxiety-related behavior and stress responsiveness. This test can be performed with direct observation and requires only relatively simple equipment, but is also amenable to computerized behavioral analysis either from recorded behavioral trials or in real time. The results of this open field test adaptation comparing across zebrafish lines are consistent with results from other tests of anxiety-related behaviors in zebrafish, supporting its use as a measure of anxiety-related behavioral phenotypes and their genetic and genomic correlates.}, booktitle={Neuromethods}, publisher={Humana Press}, author={Godwin, John and Sawyer, Susanna and Perrin, Florence and Oxendine, Sarah E. and Kezios, Zachary D.}, year={2012}, pages={181–189} }
 @article{dereje_sawyer_oxendine_zhou_kezios_wong_godwin_perrin_2012, title={Comparing behavioral responses across multiple assays of stress and anxiety in zebrafish (Danio rerio)}, volume={149}, ISSN={0005-7959 1568-539X}, url={http://dx.doi.org/10.1163/1568539x-00003018}, DOI={10.1163/1568539x-00003018}, abstractNote={Animals encounter stressful situations multiple times throughout their lives and often successfully cope with them. Individuals vary in the nature and intensity of their behavioral and physiological response to stressors, often representing correlated and qualitatively distinct coping styles (e.g., proactive and reactive). These alternative coping styles are ways an animal can overcome a variety of stressful situations, which ultimately can have important fitness consequences. Here we use zebrafish (Danio rerio) recently wild-derived and selectively bred for amount of stationary behavior (High and Low lines) and a classic domesticated strain (AB) to document the utility of these zebrafish strains in understanding coping mechanisms. The Low Stationary Behavior (LSB) line of zebrafish displayed significantly lower stress and anxiety-related behaviors than the High Stationary Behavior (HSB) across six stress and anxiety-related behavioral assays. In some assays, we observed strain differences in behavior within three minutes of the start of the trial. Males also showed reduced levels of anxiety-related behaviors relative to females in two assays. Comparing wild-derived and domesticated strains, the AB line displayed significantly lower levels of anxietyrelated behavior in half of the assays. This study demonstrates that our selectively bred lines from wild-caught zebrafish (HSB, LSB) exhibit consistent and divergent behavioral stress responses across multiple distinct assays. Hence these lines may prove useful in understanding the proximate and ultimate mechanisms of coping with stress and anxiety.}, number={10-12}, journal={Behaviour}, publisher={Brill}, author={Dereje, Simone and Sawyer, Susanna and Oxendine, Sarah E. and Zhou, Linran and Kezios, Zachary D. and Wong, Ryan Y. and Godwin, John and Perrin, Florence}, year={2012}, pages={1205–1240} }
 @misc{godwin_thompson_2012, title={Nonapeptides and Social Behavior in Fishes}, volume={61}, ISSN={["1095-6867"]}, DOI={10.1016/j.yhbeh.2011.12.016}, abstractNote={The nonapeptide hormones arginine vasotocin and isotocin play important roles in mediating social behaviors in fishes. Studies in a diverse range of species demonstrate variation in vasotocin neuronal phenotypes across within and between sexes and species as well as effects of hormone administration on aggressive and sexual behaviors. However, patterns vary considerably across species and a general explanatory model for the role of vasotocin in teleost sociosexual behaviors has proven elusive. We review these findings, examine potential explanations for the lack of agreement across studies, and propose a model based on the parvocellular AVT neurons primarily mediating social approach and subordinance functions while the magnocellular and gigantocellular AVT neurons mediate courtship and aggressive behaviors. Isotocin neuronal phenotypes and effects on behavior are relatively unstudied, but research to date suggests this will be a fruitful line of inquiry. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.}, number={3}, journal={HORMONES AND BEHAVIOR}, author={Godwin, John and Thompson, Richmond}, year={2012}, month={Mar}, pages={230–238} }
 @article{scarlata_elias_godwin_powell_shepherdson_shipley_brown_2012, title={Relationship between fecal hormone concentrations and reproductive success in captive pygmy rabbits (Brachylagus idahoensis)}, volume={93}, ISSN={["1545-1542"]}, DOI={10.1644/11-mamm-a-223.1}, abstractNote={Abstract The Columbia Basin pygmy rabbit (Brachylagus idahoensis) is critically endangered and the focus of a captive-breeding program. However, reproductive success in captivity to date has not been sufficient to sustain reintroduction efforts. The goal of this study was to investigate patterns of fecal progestagen and glucocorticoid excretion in females during mating, gestation, and lactation and identify hormonal relationships to reproductive success. Fresh fecal samples were collected from 48 adult, female rabbits over 3 breeding seasons at a frequency of 4–7 samples per week. Results showed that a large (17-fold) increase in progestagen concentrations 1 day after mating provides a reliable means of determining if a successful mating occurred. In general, higher glucocorticoid concentrations during the breeding season, specifically during mating and gestation, were associated with lower reproductive success. Females that failed to conceive during the breeding season had higher glucocorticoid and lower progestagen baseline concentrations than females that did conceive. Glucocorticoid excretion during late gestation, but not lactation, was negatively associated with litter success, suggesting it affects offspring survival more during the prenatal than the postnatal period. Progestagen and glucocorticoid concentrations at the end of gestation were positively related to litter size, which may be an important factor in juvenile survival. In summary, higher concentrations of fecal glucocorticoids during the breeding season were associated with reduced conception rates and survival of subsequent litters. Ultimately, identifying what factors cause elevated glucocorticoids in pygmy rabbits could provide opportunities to alleviate negative stressors and increase the reproductive output of the captive population.}, number={3}, journal={JOURNAL OF MAMMALOGY}, author={Scarlata, Candace D. and Elias, Becky A. and Godwin, John R. and Powell, Roger A. and Shepherdson, David and Shipley, Lisa A. and Brown, Janine L.}, year={2012}, month={Jun}, pages={759–770} }
 @article{lema_slane_salvesen_godwin_2012, title={Variation in gene transcript profiles of two V1a-type arginine vasotocin receptors among sexual phases of bluehead wrasse (Thalassoma bifasciatum)}, volume={179}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2012.10.001}, abstractNote={The neurohypophyseal hormone arginine vasotocin (AVT) mediates behavioral and reproductive plasticity in vertebrates, and has been linked to the behavioral changes associated with protogyny in the bluehead wrasse (Thalassoma bifasciatum). In this study, we sequenced full-length cDNAs encoding two distinct V1a-type AVT receptors (v1a1 and v1a2) from the bluehead wrasse, and examined variation in brain and gonadal abundance of these receptor transcripts among sexual phases. End point RT-PCR revealed that v1a1 and v1a2 transcripts varied in tissue distribution, with v1a1 receptor mRNAs at greatest levels in the telencephalon, hypothalamus, optic tectum, cerebellum and testis, and v1a2 receptor transcripts most abundant in the hypothalamus, cerebellum and gills. In the brain, v1a1 and v1a2 mRNAs both localized by in situ hybridization to the dorsal and ventral telencephalon, the preoptic area of the hypothalamus, the ventral hypothalamus and lateral recess of the third ventricle. Quantitative real-time RT-PCR revealed that relative abundance of these two receptor mRNAs varied significantly in brain and gonad with sexual phase. Relative levels of v1a2 mRNAs were greater in whole brain and isolated hypothalamus of terminal phase (TP) male wrasse compared to initial phase (IP) males or females. In the gonad, v1a1 mRNAs were at levels 2.5-fold greater in the testes of IP males - and 4-5-fold greater in the testes of TP males - compared to the ovaries of females. These results provide evidence that V1a-type AVT receptor transcript abundance in the hypothalamus and gonads of bluehead wrasse varies in patterns linked to sexual phase, and bestow a foundation for future studies investigating how differential expression of v1a1 and v1a2 teleost AVT receptors links to behavioral status and gonadal function in fish more broadly.}, number={3}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Lema, Sean C. and Slane, Melissa A. and Salvesen, Kelley E. and Godwin, John}, year={2012}, month={Dec}, pages={451–464} }
 @article{scarlata_elias_godwin_powell_shepherdson_shipley_brown_2011, title={Characterizing gonadal and adrenal activity by fecal steroid analyses in pygmy rabbits (Brachylagus idahoensis)}, volume={171}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2011.03.002}, abstractNote={In 2001, the sudden collapse of the Columbia Basin population of pygmy rabbits prompted the initiation of a captive breeding program to facilitate reintroduction, but reproductive success in captivity has not met expectations. Therefore, the objective of this study was to characterize the reproductive and adrenal endocrinology of this endangered rabbit species so that appropriate management strategies could be developed to monitor animal welfare and increase reproduction. Fecal samples were collected from 27 female pygmy rabbits over three breeding and non-breeding seasons. HPLC analyses verified the presence of progesterone in the excreta of pygmy rabbits, but the majority of progestagen metabolites were unidentified polar compounds. By contrast, >70% of glucocorticoid immunoactivity was associated with cortisol. Longitudinal fecal hormone profiles during pregnancy were characterized by a large spike in progestagens shortly after mating, a gradual increase in progestagen and glucocorticoid concentrations throughout gestation and a return of hormones to baseline soon after birth (Day 24). The spike in progestagens 1 day after mating was a significant discovery for this species and appears to provide a reliable means of determining if a successful mating has occurred. Seasonal analyses of hormone excretion found that progestagen baselines did not vary between the breeding and non-breeding seasons, but, as expected, were highest during the breeding season in association with pregnancy. Across seasons, the lowest concentrations of glucocorticoids were associated with the highest rates of offspring production and survival, suggesting a possible link between heightened adrenal activity and lowered reproductive fitness in pygmy rabbits.}, number={3}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Scarlata, Candace D. and Elias, Becky A. and Godwin, John R. and Powell, Roger A. and Shepherdson, David and Shipley, Lisa A. and Brown, Janine L.}, year={2011}, month={May}, pages={373–380} }
 @article{mccaffrey_hawkins_godwin_2011, title={Sexual Phenotype Differences in zic2 mRNA Abundance in the Preoptic Area of a Protogynous Teleost, Thalassoma bifasciatum}, volume={6}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0023213}, abstractNote={The highly conserved members of the zic family of zinc-finger transcription factors are primarily known for their roles in embryonic signaling pathways and regulation of cellular proliferation and differentiation. This study describes sexual phenotype differences in abundances of zic2 mRNA in the preoptic area of the hypothalamus, a region strongly implicated in sexual behavior and function, in an adult teleost, Thalassoma bifasciatum. The bluehead wrasse (Thalassoma bifasciatum) is a valuable model for studying neuroendocrine processes because it displays two discrete male phenotypes, initial phase (IP) males and territorial, terminal phase (TP) males, and undergoes socially-controlled protogynous sex change. Previously generated microarray-based comparisons suggested that zic2 was upregulated in the brains of terminal phase males relative to initial phase males. To further explore this difference, we cloned a 727 bp sequence for neural zic2 from field-collected animals. Riboprobe-based in situ hybridization was employed to localize zic2 signal in adult bluehead brains and assess the relative abundance of brain zic2 mRNA across sexual phenotypes. We found zic2 mRNA expression was extremely abundant in the granular cells of the cerebellum and widespread in other brain regions including in the thalamus, hypothalamus, habenula, torus semicircularis, torus longitudinalis, medial longitudinal fascicle and telencephalic areas. Quantitative autoradiography and phosphorimaging showed zic2 mRNA hybridization signal in the preoptic area of the hypothalamus was significantly higher in terminal phase males relative to both initial phase males and females, and silver grain analysis confirmed this relationship between phenotypes. No significant difference in abundance was found in zic2 signal across phenotypes in the habenula, a brain region not implicated in the control of sexual behavior, or cerebellum.}, number={8}, journal={PLOS ONE}, author={McCaffrey, Katherine and Hawkins, Mary Beth and Godwin, John}, year={2011}, month={Aug} }
 @inbook{borski_luckenbach_godwin_2010, title={Flatfish as Model Research Animals: Metamorphosis and Sex Determination}, ISBN={9780813810997 9780813809427}, url={http://dx.doi.org/10.1002/9780813810997.ch16}, DOI={10.1002/9780813810997.ch16}, abstractNote={This chapter contains sections titled: Metamorphosis Sex determination Conclusion and future research directions Acknowledgments Literature cited}, booktitle={Practical Flatfish Culture and Stock Enhancement}, publisher={Wiley-Blackwell}, author={Borski, Russell J. and Luckenbach, John Adam and Godwin, John}, year={2010}, month={Apr}, pages={286–302} }
 @inbook{godwin_2010, title={Neuroendocrine Regulation of Sex Change and Alternate Sexual Phenotypes in Sex-Changing Reef Fishes}, ISBN={9780520264335}, url={http://dx.doi.org/10.1525/california/9780520264335.003.0009}, DOI={10.1525/california/9780520264335.003.0009}, abstractNote={Our understanding of the diversity of sexual strategies occurring in nature has increased dramatically in the last 25 years. This is particularly true in the area of determination of an individual's sex by environmental signals. Progress in understanding environmental sex determination has been greatest in the areas of temperature-dependent sex determination in reptiles, and social determination of sex and sexual expression in fishes. This chapter discusses physiological and neural mechanisms underlying the expression of alternate male phenotypes in sex-changing marine fishes. First, it briefly reviews the vertebrate and teleost neuroendocrine axis, as well as key steroid and neural signaling systems known to affect reproductive function, reproductive behavior, and aggression in fishes. The chapter then explores the known involvement of these systems in regulating sex change, sexual behavior, and sexual phenotypes for the best-studied groups of tropical marine fishes in this respect: the gobies (Gobiidae); the basslets and groupers (Serranidae); and the wrasses, parrotfishes, and damselfishes (Labridae, Scaridae, and Pomacentridae).}, booktitle={Reproduction and Sexuality in Marine FishesPatterns and Processes}, publisher={University of California Press}, author={Godwin, John}, year={2010}, month={Oct}, pages={272–306} }
 @misc{godwin_2010, title={Neuroendocrinology of sexual plasticity in teleost fishes}, volume={31}, ISSN={["1095-6808"]}, DOI={10.1016/j.yfrne.2010.02.002}, abstractNote={The study of sex differences has produced major insights into the organization of animal phenotypes and the regulatory mechanisms generating phenotypic variation from similar genetic templates. Teleost fishes display the greatest diversity of sexual expression among vertebrate animals. This diversity appears to arise from diversity in the timing of sex determination and less functional interdependence among the components of sexuality relative to tetrapod vertebrates. Teleost model systems therefore provide powerful models for understanding gonadal and non-gonadal influences on behavioral and physiological variation. This review addresses socially-controlled sex change and alternate male phenotypes in fishes. These sexual patterns are informative natural experiments that illustrate how variation in conserved neuroendocrine pathways can give rise to a wide range of reproductive adaptations. Key regulatory factors underlying sex change and alternative male phenotypes that have been identified to date include steroid hormones and the neuropeptides GnRH and arginine vasotocin, but genomic approaches are now implicating a diversity of other influences as well.}, number={2}, journal={FRONTIERS IN NEUROENDOCRINOLOGY}, author={Godwin, John}, year={2010}, month={Apr}, pages={203–216} }
 @inbook{godwin_2010, title={Sex Change in Reef Fishes: Behavior and Physiology}, ISBN={9780080453378}, url={http://dx.doi.org/10.1016/b978-0-08-045337-8.00245-x}, DOI={10.1016/b978-0-08-045337-8.00245-x}, abstractNote={Socially controlled sex change in reef fishes represents an extreme example of sexual plasticity in vertebrates, but one that is both informative and experimentally useful. This plasticity is relatively well understood from an evolutionary perspective, but understanding of the physiological and neurobiological mechanisms mediating these dramatic changes in behavior and physiology is less advanced. Studies to date indicate important roles for steroid hormones and hypothalamic gonadotropin-releasing hormone neurons for gonadal change. Other studies focused on behavioral changes indicate important roles for monoamine neurotransmitters and arginine vasotocin, part of a family of neuropeptide modulators that affect social behavior in a range of vertebrates.}, booktitle={Encyclopedia of Animal Behavior}, publisher={Elsevier}, author={Godwin, J.}, year={2010}, pages={160–166} }
 @article{hueffer_armbruster_daehler_ferzli_godwin_mulder_sherwood_2010, title={Species interactions along a continuum: The fig wasp mutualism}, journal={EcoEdNet}, publisher={EcoEdNet}, author={Hueffer, K. and Armbruster, P. and Daehler, C. and Ferzli, M. and Godwin, J. and Mulder, C. and Sherwood, A.}, year={2010} }
 @misc{luckenbach_borski_daniels_godwin_2009, title={Sex determination in flatfishes: Mechanisms and environmental influences}, volume={20}, ISSN={["1096-3634"]}, DOI={10.1016/j.semcdb.2008.12.002}, abstractNote={Flounder of the genus Paralichthys exhibit a unique mode of sex determination where both low and high temperatures induce male-skewed sex ratios, while intermediate temperatures produce a 1:1 sex ratio. Male differentiation is thus easily induced in genetic females creating a combination of genetic (GSD) and environmental sex determination (ESD). Since male flounder become reproductively fit at substantially smaller body sizes than females, temperature or other environmental variables that elicit lower growth rates may also influence sex differentiation toward male development. This review covers our current knowledge of sex determination and differentiation in flatfishes including possible adaptive significance of ESD and involvement of factors such as aromatase (cyp19).}, number={3}, journal={SEMINARS IN CELL & DEVELOPMENTAL BIOLOGY}, author={Luckenbach, J. Adam and Borski, Russell J. and Daniels, Harry V. and Godwin, John}, year={2009}, month={May}, pages={256–263} }
 @misc{godwin_2009, title={Social determination of sex in reef fishes}, volume={20}, ISSN={["1084-9521"]}, DOI={10.1016/j.semcdb.2008.12.003}, abstractNote={Many fishes living in reef environments display remarkable flexibility in sexuality with social interactions determining their sex either during juvenile development or in adulthood. The evolutionary advantages of such flexibility are relatively well established. By contrast, the mechanisms by which social cues guide development of the sexual phenotype are less well understood. This paper reviews our understanding of these processes for some well-studied reef fish groups at the gonadal and neuroendocrine levels as well as proposing promising directions for future study.}, number={3}, journal={SEMINARS IN CELL & DEVELOPMENTAL BIOLOGY}, author={Godwin, John}, year={2009}, month={May}, pages={264–270} }
 @article{shewmon_godwin_murashige_daniels_2007, title={Environmental manipulation of growth and sexual maturation in yellow perch, Perca flavescens}, volume={38}, ISSN={["0893-8849"]}, DOI={10.1111/j.1749-7345.2007.00110.x}, abstractNote={Abstract}, number={3}, journal={JOURNAL OF THE WORLD AQUACULTURE SOCIETY}, author={Shewmon, Laura N. and Godwin, John R. and Murashige, Ryan S. and Daniels, Harry V.}, year={2007}, month={Sep}, pages={383–394} }
 @article{luckenbach_murashige_daniels_godwin_borski_2007, title={Temperature affects insulin-like growth factor I and growth of juvenile southern flounder, Paralichthys lethostigma}, volume={146}, ISSN={["1531-4332"]}, DOI={10.1016/j.cbpa.2006.09.024}, abstractNote={Temperature profoundly influences growth of heterothermic vertebrates. However, few studies have investigated the effects of temperature on growth and insulin-like growth factor I (IGF-I) in fishes. The aim of this study was to examine effects of temperature on growth and establish whether IGF-I may mediate growth at different temperatures in southern flounder, Paralichthys lethostigma. In two experiments, juvenile flounder were reared at 23 and 28 degrees C and growth was monitored for either 117 or 197 days. Growth was similar across treatments in both experiments until fish reached approximately 100 mm total length. Body size then diverged with fish at 23 degrees C ultimately growing 65-83% larger than those at 28 degrees C. Muscle IGF-I mRNA, plasma IGF-I, and hepatosomatic index (HSI) were significantly higher in flounder at 23 degrees C, whereas hepatic IGF-I mRNA abundance did not differ with treatment. Muscle IGF-I mRNA was correlated with HSI, while plasma IGF-I was correlated with body size, hepatic IGF-I mRNA, and HSI. These results demonstrate a strong effect of temperature on flounder growth and show that temperature-induced variation in growth is associated with differences in systemic IGF-I and local (i.e., muscle) IGF-I mRNA levels. The results also support the use of plasma IGF-I and HSI as indicators of flounder growth status.}, number={1}, journal={COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY}, author={Luckenbach, J. Adam and Murashige, Ryan and Daniels, Hany V. and Godwin, John and Borski, Russell J.}, year={2007}, month={Jan}, pages={95–104} }
 @article{marsh_creutz_hawkins_godwin_2006, title={Aromatase immunoreactivity in the bluehead wrasse brain, Thalassoma bifasciatum: Immunolocalization and co-regionalization with arginine vasotocin and tyrosine hydroxylase}, volume={1126}, ISSN={["1872-6240"]}, DOI={10.1016/j.brainres.2006.09.017}, abstractNote={Sex steroid hormones regulate various neural functions that control vertebrate sociosexual behavior. A number of sex steroids can be synthesized de novo in the brain, including estrogens by the enzyme aromatase. Aromatase, the neuropeptides arginine vasotocin/vasopressin, and the monoamine neurotransmitter dopamine have all been implicated in the control of male sexual and aggressive behavior in a variety of vertebrates. This study examined the expression of brain aromatase in the bluehead wrasse (Thalassoma bifasciatum), a teleost fish that exhibits socially controlled behavioral and gonadal sex change. We used immunocytochemistry (ICC) to characterize distributions of aromatase-immunoreactive (ir) cells, and to examine their relationship with AVT-ir neurons and tyrosine hydroxylase-ir (TH-ir) neurons in key sensory and integrative areas of the brain of this species. Aromatase-ir appeared to be in glial cell populations, and was found in the dorsal and ventral telencephalon, the preoptic area of the hypothalamus, and the lateral recess of the third ventricle, among other brain areas. Aromatase-ir fibers are closely associated with AVT-ir neurons throughout the preoptic area, indicating the potential for functional interactions. Aromatase-ir cell bodies and fibers were also co-regionalized with TH-ir neurons, suggesting possible interaction between the dopaminergic system and neural estrogen production. The presence of aromatase in brain regions important in the regulation of sexual and aggressive behavior suggests that local estrogen synthesis could regulate sex change through effects on signaling systems that subserve reproductive behavior and function.}, journal={BRAIN RESEARCH}, author={Marsh, K. Erica and Creutz, Lela M. and Hawkins, M. Beth and Godwin, John}, year={2006}, month={Dec}, pages={91–101} }
 @article{morgan_murashige_woolridge_luckenbach_watanabe_borski_godwin_daniels_2006, title={Effective UV dose and pressure shock for induction of meiotic gynogenesis in southern flounder (Paralichthys lethostigma) using black sea bass (Centropristis striata) sperm}, volume={259}, ISSN={["0044-8486"]}, DOI={10.1016/j.aquaculture.2006.05.045}, abstractNote={Female southern flounder (Paralichthys lethostigma) grow 2–3 times larger than males. Therefore, all-female production will maximize profit potential for the culture of this species. We have developed protocols to produce all-female southern flounder through induction of meiotic gynogenesis with heterologous sperm of black sea bass (Centropristis striata). Experiments were conducted to establish these practical methods using a total of 40 spawns from 32 broodstock. The first set of experiments determined the UV dose that genetically inactivated black sea bass sperm, yet retained adequate motility for activation of flounder eggs. Milt from several black sea bass was diluted 1:10 with Ringer's solution and UV irradiated with doses ranging from 0–130 J/cm2. Two criteria were utilized to evaluate the UV irradiation effects: percentage of motile sperm and duration of sperm activity. Motility and duration of activity generally decreased with increases in UV dosage. At UV doses greater than or equal to 90 J/cm2, motility was < 1.5%. Fertilization rates were significantly lower at the highest UV dose of 130 J/cm2 but were not different for the other treatments. Hatch rate was highest at 70 J/cm2. A second set of experiments examined appropriate pressure shock protocols for retention of the 2nd polar body in southern flounder eggs after activation with black sea bass sperm. A pressure shock of 8500 psi was initiated at varying times of 1, 2, and 3 min post-fertilization and maintained for 6 min. Eggs that were handled similarly, but not pressure shocked, served as negative controls. Pressure shock applied at either 1 or 2 min post-fertilization resulted in higher rates of hatch and survival. Using these methods, six separate spawns produced offspring that survived through and beyond metamorphosis. The average fertility (± SEM) was 70.9 + 12.8%. Of the fertilized eggs, percentage hatch varied with pressure shock initiation times and ranged from 1.48 + 0.52% (1 min) to 0.61 + 0.11% (3 min). Gynogenetic flounder were sex-reversed to males by high temperature and, upon reaching maturity, expressed motile sperm that resulted in successful fertilization of flounder eggs. These results indicate that the use of UV irradiated sperm from black sea bass for activation of flounder eggs and pressure shock for polar body retention is an effective method to produce gynogenetic offspring.}, number={1-4}, journal={AQUACULTURE}, author={Morgan, Andrew J. and Murashige, Ryan and Woolridge, Christopher A. and Luckenbach, J. Adam and Watanabe, Wade O. and Borski, Russell J. and Godwin, John and Daniels, Harry V.}, year={2006}, month={Sep}, pages={290–299} }
 @article{engell_godwin_young_vandenbergh_2006, title={Perinatal exposure to endocrine disrupting compounds alters behavior and brain in the female pine vole}, volume={28}, ISSN={["1872-9738"]}, DOI={10.1016/j.ntt.2005.10.002}, abstractNote={Endocrine-disrupting chemicals (EDCs) are synthetic chemicals that arise from sources such as pesticides and have the ability to mimic or inhibit gonadal steroid hormones. The objective of this research was to examine the effects of EDCs on the behaviors associated with monogamy and the expression of related neuropeptide receptors. Pine voles, a novel experimental mammal, were chosen because they display strong monogamous pair bonding. Female pine voles were orally administered estrogenic diethylstilbestrol (DES) and methoxychlor (MXC) or oil control throughout gestation and lactation of pups. Exposed pups were tested as adults. Preference for the mate and maternal behaviors were assessed. While the ability to form partner preferences was intact, DES-exposed females showed increased aggression toward a stranger, while MXC exposed females showed a strong trend toward spending more time alone. Oxytocin (OT) receptor binding in the brain was assessed for possible effects on this behaviorally important neuropeptide signaling system. The cingulate cortex showed a reduction in OT binding in the MXC group. These findings demonstrate that exposure to EDCs during pre- and neonatal development can alter female adult neural phenotype and behavior related to monogamous behavior traits.}, number={1}, journal={NEUROTOXICOLOGY AND TERATOLOGY}, author={Engell, MD and Godwin, J and Young, LJ and Vandenbergh, JG}, year={2006}, pages={103–110} }
 @article{luckenbach_early_rowe_borski_daniels_godwin_2005, title={Aromatase cytochrome P450: Cloning, intron variation, and ontogeny of gene expression in southern flounder (Paralichthys lethostigma)}, volume={303A}, ISSN={["2471-5646"]}, DOI={10.1002/jez.a.198}, abstractNote={Aromatase cytochrome P450 (P450arom) is the enzyme complex responsible for conversion of androgens to estrogens in vertebrates. Consequently, in some fishes its activity appears critical to ovarian differentiation. Southern flounder (Paralichthys lethostigma) is a commercially important flatfish in which females grow larger than males and sex determination is temperature sensitive. Through cloning of the P450arom gene in ovary and quantitative reverse transcription-polymerase chain reaction, we developed a biomarker for early female differentiation in southern flounder. The deduced amino acid sequence for southern flounder P450arom is similar to other teleosts. Comparison of P450arom intron sequences from fish of different populations revealed substantial inter-individual variation. Adult ovary and spleen exhibited high levels of P450arom mRNA, while P450arom mRNA was only weakly detected in testes. Brain, liver, intestine, kidney, gill, muscle, and heart showed little or no P450arom mRNA expression. Gonads of wild and hatchery-produced juvenile flounder of sizes spanning the period of sex differentiation initially exhibited low levels of P450arom mRNA followed by increases in some individuals and bifurcation into two clearly segregated groups (i.e., putative males and females) beginning at approximately 65 mm in total length. Gonadal histology confirmed predictions of sex based on P450arom expression in juvenile flounder, demonstrating that the patterns of P450arom expression observed relate to sex-specific differentiation. This research represents a unique approach to assessing sex differentiation in a natural population, and a powerful technique for better understanding mechanisms of flounder sex determination and rapidly defining conditions for controlling sex for aquaculture.}, number={8}, journal={JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY}, author={Luckenbach, JA and Early, LW and Rowe, AH and Borski, RJ and Daniels, HV and Godwin, J}, year={2005}, month={Aug}, pages={643–656} }
 @article{hawkins_godwin_crews_thomas_2005, title={The distributions of the duplicate oestrogen receptors ER-beta a and ER-beta b in the forebrain of the Atlantic croaker (Micropogonias undulatus): evidence for subfunctionalization after gene duplication}, volume={272}, ISSN={["1471-2954"]}, DOI={10.1098/rspb.2004.3008}, abstractNote={Teleost fishes have three distinct oestrogen receptor (ER) subtypes: ER-α, ER-βa (or ER-γ) and ER-βb. ER-βa and ER-βb arose from a duplication of an ancestralER-βgene early in the teleost lineage. Here, we describe the distribution of the three ER mRNAs in the hypothalamus and cerebellum of the Atlantic croaker to address two issues: the specific functions of multiple ERs in the neuroendocrine system and the evolution and fate of duplicated genes. ER-α was detected in nuclei of the preoptic area (POA) and hypothalamus previously shown to possess ER-αs in teleosts. AcER-βb, but not ER-βa, labelling was detected in the magnocellular neurons of the POA, nucleus posterior tuberis, the nucleus recessus posterior and cerebellum. By contrast, acER-βa, but not ER-βb, was detected in the dorsal anterior parvocellular POA and suprachiasmatic nucleus. Both ER-βs were found in posterior parvocellular and ventral anterior POA nuclei, the ventral hypothalamus, and periventricular dorsal hypothalamus. The differences we observed in ER subtype mRNA distribution within well-characterized brain nuclei suggest that ER-βa and ER-βb have distinct functions in the neuroendocrine control of reproduction and behaviour, and provide evidence that the teleostER-βparalogues have partitioned functions of the ancestralER-βgene they shared with tetrapods.}, number={1563}, journal={PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES}, author={Hawkins, MB and Godwin, J and Crews, D and Thomas, P}, year={2005}, month={Mar}, pages={633–641} }
 @article{semsar_perreault_godwin_2004, title={Fluoxetine-treated male wrasses exhibit low AVT expression}, volume={1029}, ISSN={["1872-6240"]}, DOI={10.1016/j.brainres.2004.09.030}, abstractNote={In many species, increasing serotonergic activity can reduce aggression and reverse dominance relationships. These effects may in part be mediated through interactions with the arginine vasotocin/vasopressin (AVT/AVP) system. We tested this hypothesis in a territorial coral reef fish, the bluehead wrasse (Thalassoma bifasciatum), by experimentally enhancing serotonergic neurotransmission, using the selective serotonin re-uptake inhibitor (SSRI) fluoxetine. Terminal phase (TP) males received 2 weeks of nightly intraperitoneal fluoxetine injections (6 microg/g body weight) and were then tested for their aggressive response to an intruder and killed to examine AVT phenotype in the preoptic area of the hypothalamus (POA), an area important to social behavior in fishes. Our previously published study demonstrated that fluoxetine-treated males are less aggressive [H.A.N. Perreault, K. Semsar, J. Godwin, Fluoxetine treatment decreases territorial aggression in a coral reef fish, Physiol. and Behav. 79 (2003) 719-724.]. Here, further study of these same fluoxetine-treated males shows approximately twofold lower AVT mRNA expression relative to saline-treated controls in all regions of the POA (all p< or =0.05) without any changes in AVT-ir soma size (all p>0.4). This study experimentally supports the hypothesis that behavioral effects of SSRIs may be mediated in part through interactions with the AVT/AVP system. These results parallel findings from rodents and humans and are consistent with an indirect neurosteroidogenic rather than a solely direct serotonergic mechanism for SSRI effects on the AVT/AVP system. Furthermore, they suggest that SSRI effects on neuroendocrine function may be best modeled in animals with sensitive stress responses such as those found in nondomesticated animals.}, number={2}, journal={BRAIN RESEARCH}, author={Semsar, K and Perreault, HA and Godwin, J}, year={2004}, month={Dec}, pages={141–147} }
 @article{luckenbach_godwin_daniels_beasley_sullivan_borski_2004, title={Induction of diploid gynogenesis in southern flounder (Paralichthys lethostigma) with homologous and heterologous sperm}, volume={237}, ISSN={["1873-5622"]}, DOI={10.1016/j.aquaculture.2004.05.005}, abstractNote={Effective methods for induction of diploid gynogenesis in North American flounder of the genus Paralichthys are needed to initiate monosex culture, which will allow growers to take advantage of the more rapid growth and larger size attained by females. To test methods for inducing diploid gynogenesis in southern flounder (Paralichthys lethostigma) using homologous sperm, four treatments, named for their expected outcome, were employed: haploid, diploid, triploid, and gynogenetic diploid. Diploid gynogenesis was induced by activating egg development with UV-irradiated flounder sperm (70 J/cm2) for 3–4 min in seawater, and then subjecting the eggs to cold shock in 0–2 °C seawater for 45–50 min. Cold shock was used to prevent extrusion of the second polar body. Control treatments omitted one or more of these steps to separately assess the effectiveness of UV irradiation and cold shock. Larvae were observed for physical abnormalities and then histologically processed for ploidy determination. Haploid larvae exhibited abnormal external morphology while diploid, gynogenetic diploid, and triploid larvae showed normal morphologies. Cross-sectional areas of erythrocyte nuclei were measured for larvae in each treatment group and significant differences were found. Nuclear areas for treatment groups corresponded to predicted ploidy (triploid>diploid>haploid) and did not differ between normal diploid controls and gynogenetic diploids. These results suggest that the procedures of sperm irradiation and egg cold shock successfully generated gynogenetic diploids. Due to the low volumes of semen produced by male flounder, and to eliminate any potential genetic contribution by homologous sperm, activation of flounder eggs with heterologous sperm was also investigated. Induction of diploid gynogenesis was successful when flounder eggs were fertilized with irradiated (50 J/cm2) sperm from striped mullet (Mugil cephalus), and then cold shocked. This work provides procedures for induction of diploid gynogenesis in southern flounder using homologous and heterologous sperm, and validates a method for verification of ploidy in larval fish.}, number={1-4}, journal={AQUACULTURE}, author={Luckenbach, JA and Godwin, J and Daniels, HV and Beasley, JM and Sullivan, CV and Borski, RJ}, year={2004}, month={Aug}, pages={499–516} }
 @article{semsar_godwin_2004, title={Multiple mechanisms of phenotype development in the bluehead wrasse}, volume={45}, ISSN={["1095-6867"]}, DOI={10.1016/j.yhbeh.2004.01.003}, abstractNote={Despite having detailed information on mechanisms mediating sex-typical behavior in many species, we have little understanding of whether the same mechanisms regulate these behaviors when they are performed in the same species under different social contexts. In the five field experiments of this study of bluehead wrasses (Thalassoma bifasciatum), a sex-changing fish, we examined the roles of arginine vasotocin (AVT) and the potent teleost androgen 11-ketotestosterone (11KT) in mediating sexual and aggressive behaviors typical of dominant males. We demonstrated that AVT appears necessary for the assumption of dominant territorial status in males and females, but is sufficient only in the socially dominant terminal phase (TP) male phenotype. Specifically, an AVP V1 receptor antagonist prevented both TP males and females from gaining dominance over recently vacated territories. However, unlike TP males in a previous study, neither females nor initial phase males responded to AVT treatment with increases in display of TP male typical behaviors when under social conditions that inhibit sex change. Treating females with 11KT did not alter responsiveness to AVT, but did induce male coloration and courtship behavior that was not observed in oil-treated females. Combined with the results of a previous study, these results indicate that the ability of AVT to induce male-typical behavior differs among sexual phenotypes and that this differential responsiveness appears to be dependent on social context and not directly on exposure to 11KT. Furthermore, since 11KT can induce courtship behavior in females that is not affected by AVT, there may be different hormonal mechanisms mediating courtship behavior under different social contexts.}, number={5}, journal={HORMONES AND BEHAVIOR}, author={Semsar, K and Godwin, J}, year={2004}, month={May}, pages={345–353} }
 @article{godwin_luckenbach_borski_2003, title={Ecology meets endocrinology: environmental sex determination in fishes}, volume={5}, ISSN={["1525-142X"]}, DOI={10.1046/j.1525-142X.2003.03007.x}, abstractNote={Van Valen (1973) characterized evolution as the control of development by ecology. Sex determination in fishes provides some clear examples of this “control” in operation. Teleost fishes show a remarkable variety of sex determination and differentiation patterns. These range from systems in which sex is determined by sex chromosomes, as in birds and mammals, to simultaneous hermaphrodites that alternate spawning as a female and male on a second to second basis. This extraordinary flexibility may result from a combined lack of developmental constraint on reproductive structures in many lineages and selection for sexual lability in the face of environmental unpredictability. This review addresses environmental influences on sex determination and differentiation in fishes. There is a variety of documented environmental influences on sex determination (ESD) in fishes. We focus here on two classes of examples where the key environmental cues are of clear ecological relevance, the effects appear especially likely to be important as a normal part of the life history, and where there is evidence suggesting the sexual patterns observed represent adaptations that increase individual fitness. These classes are sex determination that is controlled by social interactions (behavioral sex determination [BSD]) (Crews 1993) and temperaturedependent sex determination (TSD). Sex determination controlled by social influences can occur before or after sexual maturation but appears to maximize the expected reproductive success of individuals in both cases. Here we first address BSD and then TSD in fishes. For each pattern of sex determination, we discuss selection pressures that appear to favor these patterns, examples of each, and what is known regarding the underlying physiological mechanisms. For more comprehensive and general reviews of patterns and mechanisms of sex determination in fishes, the reader is referred to several excellent reviews (Nakamura et al. 1998; Baroiller et al. 1999; Baroiller and D’Cotta 2001; Piferrer 2001). The major focus in studies of physiological mediation of teleost sex determination is what is referred to by endocrinologists as the hypothalamo-pituitary-gonadal (HPG) axis (Fig. 1). This axis consists primarily of hypothalamic neurosecretory neurons producing gonadotropin-releasing hormone (GnRH), gonadotropins produced in and released from the pituitary gland (GtH I and GtH II), and the gonad as the major site of steroid biosynthesis with its steroid metabolizing enzymes, steroid hormone receptors, and a variety of other proteins that mediate steroid hormone action. One steroid biosynthetic enzyme that has been a particularly fruitful focus in correlative and manipulative studies of vertebrate sex determination is cytochrome P-450 aromatase. This enzyme catalyzes the conversion of androgens to estrogens (primarily testosterone to estradiol-17 ). Aromatase expression correlates with female determination in a variety of vertebrates, and aromatasespecific antagonists can block female development in fishes, amphibians, reptiles, and birds (Elbrecht and Smith 1992; Lance and Bogart 1992; Crews et al. 1994; Wennstrom and Crews 1995; Kitano et al. 1999; D’Cotta et al. 2001). Estradiol-17 plays a central role in female reproductive physiology in fishes, whereas the androgen 11-ketotestosterone (11-KT) is crucial to gamete maturation and the expression of secondary sexual characteristics in males (Borg 1994; Brantley et al. 1993). Importantly, testosterone levels often do not differ between male and female fishes or are higher in females (Borg 1994). Because of the central role of aromatase in the biosynthesis of estrogens, it will be a focus in consideration of mechanisms by which environmental information leads to sex determination responses. More generally, our understanding of vertebrate sexual function indicates the HPG axis plays the key role in transducing environmental information into gonadal determination, differentiation, and maturation events. A general theme of this review is where and how this transduction may occur in the HPG axis.}, number={1}, journal={EVOLUTION & DEVELOPMENT}, author={Godwin, J and Luckenbach, JA and Borski, RJ}, year={2003}, pages={40–49} }
 @article{perreault_semsar_godwin_2003, title={Fluoxetine treatment decreases territorial aggression in a coral reef fish}, volume={79}, ISSN={["0031-9384"]}, DOI={10.1016/S0031-9384(03)00211-7}, abstractNote={Serotonin is an important neurotransmitter in the regulation of social interactions in many animals. Correlative studies in numerous vertebrate species, including fishes, indicate that aggressive males have lower relative serotonergic activity than less aggressive males. We used fluoxetine, a selective serotonin reuptake inhibitor, to experimentally enhance serotonergic neurotransmission in a territorial coral reef fish and test the role of this neurotransmitter in mediating aggressive behavior and dominance interactions. The bluehead wrasse, Thalassoma bifasciatum, has a complex social system in which large males aggressively defend spawning territories from intruders. In separate experiments, we tested the effects of chronic and acute fluoxetine treatments on aggressive behavior using a resident-intruder design. In a laboratory experiment, males treated daily with intraperitoneal fluoxetine injections for 2 weeks (6 microg/g bw) displayed fewer intruder chases than saline-treated controls. Chronically fluoxetine-treated males also showed lower levels of activity than saline controls prior to intruder trials. However, activity was not correlated with chases on an individual level, indicating the lower aggression displayed by fluoxetine-treated males was not due solely to general reductions in behavioral display. A field study exposed males to a confined territorial intruder following single intraperitoneal injections of fluoxetine (10 microg/g bw) or saline given to the same individual on different days. The frequency of aggressive chases following acute fluoxetine treatment was significantly lower than that following saline injections. This study experimentally supports the link between serotonin and aggressive behavior in fishes in both a controlled laboratory testing environment and the animal's natural habitat.}, number={4-5}, journal={PHYSIOLOGY & BEHAVIOR}, author={Perreault, HAN and Semsar, K and Godwin, J}, year={2003}, month={Sep}, pages={719–724} }
 @article{luckenbach_godwin_daniels_borski_2003, title={Gonadal differentiation and effects of temperature on sex determination in southern flounder (Paralichthys lethostigma)}, volume={216}, ISSN={["0044-8486"]}, DOI={10.1016/S0044-8486(02)00407-6}, abstractNote={Southern flounder (Paralichthys lethostigma) support valuable North American fisheries and show great promise for aquaculture. Because females grow faster and reach larger adult sizes than males, monosex culture of females is desirable for commercial operations. A detailed understanding of sexual development and its timing is critical to control sex and optimize culture. Structural and cellular sex-distinguishing markers were identified histologically, and then used to describe ovarian development in female and testicular development in male flounder. In presumptive ovaries of southern flounder, development of an ovarian cavity first occurs in fish ranging from 75 to 100 mm total length (TL). This is considerably delayed relative to that observed in the Japanese congener, Paralichthys olivaceus, where an ovarian cavity is seen in fish as small as 40 mm TL. The smallest southern flounder that possessed primary oocytes in the early perinucleolus stage was 115 mm TL. In presumptive testes, the formation of seminiferous tubules first occurs in fish of approximately 100 mm TL. Spermatogonia remained quiescent until most fish were over 100 mm TL. Overall, gonads from southern flounder greater than 120 mm TL commonly possess gonial cells undergoing meiosis, clearly differentiating sex. The effect of temperature on sex determination in southern flounder was addressed in a separate experiment. Juvenile southern flounder were grown at 18, 23, or 28°C for 245 days. High and low temperatures induced phenotypic sex reversal in juvenile southern flounder, producing a higher proportion of males (96% males at high temperature, P<0.001, 78% males at low temperature, P<0.01). Raising southern flounder at the midrange temperature held sex ratios close to 1:1. Sex ratios from these trials suggest that southern flounder possess a temperature-sensitive mechanism of sex determination similar to that shown for P. olivaceus, but possibly shifted towards warmer temperatures. These findings indicate that sex differentiation in southern flounder is distinguishable in most fish by 100–120 mm TL and that sex determination is sensitive to temperature. This information is critical to the development of strategies to maximize the number of faster-growing females for commercial flounder culture.}, number={1-4}, journal={AQUACULTURE}, author={Luckenbach, JA and Godwin, J and Daniels, HV and Borski, RJ}, year={2003}, month={Feb}, pages={315–327} }
 @article{semsar_godwin_2003, title={Social influences on the arginine vasotocin system are independent of gonads in a sex-changing fish}, volume={23}, DOI={10.1523/jneurosci.23-10-04386.2003}, abstractNote={Many neuropeptide systems subserving sex-typical behavior are dependent on sex steroids for both their organization early in life and activation during maturity. The arginine vasopressin/vasotocin (AVP/AVT) system is strongly androgen dependent in many species and critically mediates responses to sociosexual stimuli. The bluehead wrasse is a teleost fish that exhibits a female-to-male sex change in response to social cues, and neither the development nor the maintenance of male-typical behavior depends on the presence of gonads. To examine social and gonadal inputs on the AVP/AVT system in the preoptic area (POA) of the hypothalamus, we conducted three field experiments. In the first experiment, we found that AVT mRNA abundance is higher in sex-changing females that attain social dominance and display dominant male behavior than in subordinate females, regardless of whether the dominant females were intact or ovariectomized. However, AVT-immunoreactive (IR) soma size in the gigantocellular POA (gPOA), but not in the magnocellular or parvocellular POA, increased only when females were displaying both dominant male behavior and had developed testes. In the second experiment, castration of dominant terminal-phase males had no effect on AVT mRNA abundance or any behavior we measured but did increase gPOA AVT-IR soma size compared with sham-operated controls. In the third experiment, 11-ketotestosterone implants in socially subordinate, ovariectomized females had no effect on either AVT mRNA abundance or AVT-IR soma size compared with controls. These results demonstrate that the AVT neural phenotype in the bluehead wrasse can be strongly influenced by social status, and that these social influences can be manifested independent of gonads.}, number={10}, journal={Journal of Neuroscience}, author={Semsar, K. and Godwin, John}, year={2003}, pages={4386–4393} }
 @article{salek_sullivan_godwin_2002, title={Arginine vasotocin effects on courtship behavior in male white perch (Morone americana)}, volume={133}, ISSN={["1872-7549"]}, DOI={10.1016/S0166-4328(02)00003-7}, abstractNote={Arginine vasotocin (AVT) and its mammalian homologue, arginine vasopressin (AVP), have been shown to have widespread behavioral effects in vertebrates. AVT was evaluated for its effectiveness in stimulating an important courtship behavior termed 'attending' in male white perch, Morone americana. Attending consists of close and continuous following of the female with occasional contact in the abdominal area. We tested the behavioral effectiveness of AVT in stimulating attending when administered either intraperitoneally (IP) or intracerebroventricularly (ICV). We also tested IP injections of AVT alone and in combination with an AVP V(1) receptor antagonist (Manning compound). None of the IP injections of either AVT or Manning compound produced consistent effects on attending behavior. In contrast, ICV injections of AVT did significantly increase attending behavior and at low dosages. Circulating levels of testosterone and 11-ketotestosterone were not affected approximately 80 min following injection by any of the treatments. The strong behavioral effects observed with ICV administration support a central site of action for AVT in stimulating attending behavior. This is a complex behavior that shows similarities to behaviors mediated by AVT and AVP in other vertebrates, providing further evidence of a conserved behavioral role for these peptides.}, number={2}, journal={BEHAVIOURAL BRAIN RESEARCH}, author={Salek, SJ and Sullivan, CV and Godwin, J}, year={2002}, month={Jul}, pages={177–183} }
 @inbook{godwin_crews_2002, title={Hormones, brain, and behavior in reptiles}, volume={2}, ISBN={0125321066}, DOI={10.1016/b978-012532104-4/50032-9}, booktitle={Hormones, brain, and behavior}, publisher={Amsterdam ; Boston: Academic Press}, author={Godwin, John and Crews, D.}, year={2002}, pages={545–585} }
 @inproceedings{semsar_godwin_2002, title={Multiple mechanisms for phenotype development}, volume={42}, number={6}, booktitle={Integrative and Comparative Biology}, author={Semsar, K. and Godwin, J.}, year={2002}, pages={1309} }
 @article{luckenbach_godwin_daniels_borski_2002, title={Optimization of North American flounder culture: a controlled breeding scheme.}, volume={33}, number={1}, journal={World Aquaculture}, author={Luckenbach, J. A. and Godwin, J. and Daniels, H. V. and Borski, R. J.}, year={2002}, pages={40–4569} }
 @article{salek_godwin_sullivan_stacey_2001, title={Courtship and tank spawning behavior of temperate basses (Genus Morone)}, volume={130}, ISSN={["0002-8487"]}, DOI={10.1577/1548-8659(2001)130<0833:CATSBO>2.0.CO;2}, abstractNote={Abstract Special arenas were used to observe and describe courtship and spawning behavior of captive striped bass Morone saxatilis, white bass Morone chrysops, and white perch Morone americana. To induce final gonadal maturation and spawning, fish were either implanted with gonadotropin-releasing hormone analog, injected with human chorionic gonadotropin, or both. Behaviors were videotaped and systematically quantified. Broodfish displayed courtship behavior for at least 5 h before spawning, characterized by one female and from one to five males releasing gametes at the water surface. Spawning lasted about 10 s for striped bass, 5 s for white bass, and less than 1 s for white perch. The best predictor of imminent spawning was a significant increase in male attending behavior, defined as extremely close and continuous following of the female, sometimes contacting her abdominal or vent area with the snout. Around the time of spawning, male striped bass attended females less intensely than did white bass or ...}, number={5}, journal={TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY}, author={Salek, SJ and Godwin, J and Sullivan, CV and Stacey, NE}, year={2001}, month={Sep}, pages={833–847} }
 @article{salek_sullivan_godwin_2001, title={Courtship behavior of male white perch, Morone americana: evidence for control by androgens}, volume={130}, ISSN={["1531-4332"]}, DOI={10.1016/s1095-6433(01)00405-6}, abstractNote={Courtship behaviors are androgen-dependent in many vertebrates and castration often decreases courtship. We examined the effectiveness of castration in reducing courtship behaviors and 11-ketotestosterone (KT) and testosterone (T) in restoring them in male white perch. Castrates were given implants containing KT, T or no hormone. Sham-operated males received implants without hormone. Three weeks later, males were exposed to an ovulated female for 1 h and two courtship behaviors were quantified. Attending behavior involves close and continuous following of a female with occasional contact. Circling involves rapid transits around the female in a circular pattern or back and forth in front of her. In plasma samples taken immediately after observations, KT and T were below detectable levels in castrated males but at high physiological levels in males implanted with KT or T. Castrated males given KT attended females more than castrated males given T implants or implants containing no hormone, but not more than sham-operated males. Circling was eliminated by castration but restored by implantation with T or 11-KT to values exhibited by sham-operated males. This is one of the few demonstrations that KT can regulate courtship behavior in a non-territorial and economically important fish species.}, number={4}, journal={COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY}, author={Salek, SJ and Sullivan, CV and Godwin, J}, year={2001}, month={Nov}, pages={731–740} }
 @article{semsar_kandel_godwin_2001, title={Manipulations of the AVT system shift social status and related courtship and aggressive behavior in the bluehead wrasse}, volume={40}, ISSN={["1095-6867"]}, DOI={10.1006/hbeh.2001.1663}, abstractNote={Arginine vasotocin (AVT) and its mammalian homologoue arginine vasopressin (AVP) influence male sexual and aggressive behaviors in many species. We tested the effects of AVT and an AVP-V(1a) receptor antagonist on the display of alternative male tactics in a tropical coral reef fish, the bluehead wrasse Thalassoma bifasciatum. We gave AVT injections to territorial and nonterritorial males of the large and colorful phenotype (terminal phase) and an AVP-V(1a) receptor antagonist, Manning compound, to territorial males in the field. AVT increased courtship independent of status, while its effects on territoriality and aggression were dependent upon male status. In territorial males, AVT increased courtship and tended to decrease the number of chases toward initial phase individuals. In nonterritorial males, AVT increased courtship, chases toward initial phase individuals, and territorial behavior while decreasing feeding. These are all behaviors rarely seen in nonterritorial males, so AVT made these males act like territorial TP males. The AVP-V(1a) receptor antagonist had opposite effects. It decreased courtship and territorial defense, making these males act more like nonterritorial males. Manipulations of the AVT system shifted males within a single phenotype from the nonterritorial social status to the territorial social status and vice versa. Since the entire suite of behaviors related to territoriality was affected by AVT system manipulations, our results suggest that the AVT system may play a key role in motivation of behaviors related to mating.}, number={1}, journal={HORMONES AND BEHAVIOR}, author={Semsar, K and Kandel, FLM and Godwin, J}, year={2001}, month={Aug}, pages={21–31} }
 @article{hartman_nag_p._crews_2000, title={Androgenic regulation of steroid hormone receptor mRNAs in the brain of whiptail lizards}, volume={12}, DOI={10.1046/j.1365-2826.2000.00513.x}, abstractNote={Sex and species differences in androgenic regulation of steroid hormone receptor mRNAs were examined in the diencephalon of two species of whiptail lizards: Cnemidophorus inornatus is a sexual species and the direct evolutionary ancestor to Cnemidophorus uniparens, an all‐female parthenogenetic species. Lizards were gonadectomized and treated with different doses of either aromatizable testosterone or nonaromatizable dihydrotestosterone. The relative abundances of androgen‐, oestrogen‐, and progesterone‐receptor mRNAs were compared in various nuclei following in situ hybridization with homologous riboprobes. A diversity of patterns in androgenic regulation was observed, with effects differing according to brain region, the steroid‐receptor mRNA being considered and, in some cases, between androgens. In the ancestral sexual species, intact males had lower androgen‐receptor mRNA abundances than castrated, blank‐implanted males in the medial preoptic area. Testosterone significantly decreased androgen‐receptor mRNA abundance in the medial preoptic area of castrated males. Males had higher androgen‐receptor mRNA levels in the preoptic area than females generally and neither the sexual or parthenogenetic females showed a decrease in androgen‐receptor mRNA with androgen treatment. Both testosterone and dihydrotestosterone increased oestrogen‐receptor mRNA abundance in the ventromedial hypothalamus of C. inornatus, but no sex differences in this effect were observed. Gonadectomy decreased, whereas androgen treatment increased, progesterone‐receptor mRNA abundance in the ventromedial hypothalamus. There was a sex difference in this response to androgen in the sexual species, with males having greater amounts than females in this brain area. The parthenogenetic species exhibited a similar pattern to females of the sexual species, but the levels were higher overall, possibly because Cnemidophorus uniparens is triploid. The periventricular preoptic area showed a different pattern, with testosterone treatment increasing progesterone‐receptor mRNA abundance in both sexes of the sexual species and in the parthenogenetic species, while dihydrotestosterone did not. The diversity of patterns in androgen effects indicates that gonadal sex, aromatization of androgen, and perhaps gene dosage all influence the expression of steroid‐receptor mRNAs in the lizard brain.}, number={2000}, journal={Journal of Neuroendocrinology}, author={Hartman, Godwin J. and Nag, V. and P. and Crews, D.}, year={2000}, pages={599–606} }
 @article{godwin_sawby_warner_crews_grober_2000, title={Hypothalamic arginine vasotocin mRNA abundance variation across sexes and with sex change in a coral reef fish}, volume={55}, ISSN={["1421-9743"]}, DOI={10.1159/000006643}, abstractNote={Gonadal hormones are important mediators of sexual and aggressive behavior in vertebrates. Recent evidence suggests that the peptide hormones arginine vasotocin (AVT) and its mammalian homologue arginine vasopressin (AVP) often critically mediate these gonadal hormone effects on behavior and have direct influences on behavioral variation. Behavioral differences between sexes, across reproductive states, and even among closely related species are correlated with differences in central AVT/AVP systems in many species. We report differences in hypothalamic AVT mRNA levels between distinct alternate male phenotypes and with female-to-male sex change in the bluehead wrasse <i>(Thalassoma bifasciatum),</i> a teleost fish. The aggressively dominant and strongly courting male phenotype has greater numbers of AVT mRNA producing cells in the magnocellular preoptic area of the hypothalamus than females. Levels of AVT mRNA within these cells in dominant males are also approximately three times female levels whereas the non-aggressive male phenotype has AVT mRNA levels approximately twice female levels. Behavioral sex change is very rapid in this species and is not dependent on the presence of gonads. Conversely, rapid increases in sexual and aggressive behavior during sex change are closely paralleled by approximate fourfold increases in hypothalamic AVT-mRNA levels. The behavioral plasticity shown by bluehead wrasses in response to social environment might be mediated in part by a neuropeptide, AVT, with changes in the gonads and gonadal hormones as the result rather than the cause of behavioral dominance.}, number={2}, journal={BRAIN BEHAVIOR AND EVOLUTION}, author={Godwin, J and Sawby, R and Warner, RR and Crews, D and Grober, MS}, year={2000}, month={Feb}, pages={77–84} }
 @article{godwin_crews_1997, title={Hormonal regulation of progesterone receptor mRNA expression in the hypothalamus of whiptail lizards: Regional and species differences}, volume={39}, DOI={10.1002/(sici)1097-4695(199905)39:2<287::aid-neu12>3.0.co;2-t}, abstractNote={The effects of gonadal steroid hormones on steroid receptor mRNA expression vary across nuclei within the brain, between the sexes, and between species. We report that exogenous estrogen increases progesterone receptor (PR) mRNA levels in the periventricular preoptic area in an ancestor and descendant species pair of whiptail lizards, and also that this effect of estrogen is significantly stronger in females of the descendant species. Second, while progesterone strongly decreases PR mRNA in the ventromedial hypothalamus of whiptail lizards and rodents, we find that there is no discernible effect of progesterone on PR mRNA levels in the periventricular preoptic area in females of the ancestral member of this species pair. These findings are a further demonstration of the variability of steroid effects on steroid receptor mRNA levels across brain nuclei. This variability may be important both in behavioral transitions over the course of the ovarian cycle in this ancestor-descendant species pair of lizards and in the evolution of pseudosexual behavior in the descendant parthenogen species.}, number={1999}, journal={Journal of Neurobiology}, author={Godwin, John and Crews, D.}, year={1997}, pages={287–293} }
 @article{godwin_crews_1997, title={Sex differences in the nervous system of reptiles}, volume={17}, ISSN={["0272-4340"]}, DOI={10.1023/A:1022586003789}, abstractNote={1. The study of sex differences in the brain and behavior of reptiles presents an excellent opportunity both to discern general principles of sexual differentiation in the nervous system and to explore the evolutionary history of this process in amniote vertebrates. 2. Findings in several reptiles suggest that some sex differences found in mammals and birds are conserved while others are not. Conserved features include areas in the limbic forebrain involved in the regulation of social and sexual behaviors. As in mammals and birds, it is rare to find differences in the distribution of sex steroid concentrating neurons in reptiles but common to find differences in the distribution of the various steroid hormone receptors and in their regulation. 3. This research has revealed that differences in social and sexual behavior are reflected better by the activity, not by the size, of hormone-sensitive limbic areas. 4. Finally, species differences in plasma levels of sex hormones are paralleled by differences in behavioral sensitivity to these hormones as well as by differences in the regulation of genes coding for steroid hormone receptors.}, number={6}, journal={CELLULAR AND MOLECULAR NEUROBIOLOGY}, author={Godwin, J and Crews, D}, year={1997}, month={Dec}, pages={649–669} }
 @article{godwin_crews_warner_1996, title={Behavioural sex change in the absence of gonads in a coral reef fish}, volume={263}, ISSN={0962-8452 1471-2954}, url={http://dx.doi.org/10.1098/rspb.1996.0246}, DOI={10.1098/rspb.1996.0246}, abstractNote={It is an axiom of vertebrate behavioural endocrinology that full expression of a male behavioural phenotype depends on testicular influences during development, in adulthood, or both. Sex change in fishes challenges this necessity: behavioural changes are often rapid and greatly precede gonadal changes. However, steroid hormones can have fast actions on the nervous system, so gonadal influences on behavioural sex change cannot be excluded based solely on the speed of these changes. We report that surgical gonad removal does not prevent or discernibly alter female-to-male behavioural sex change in a protogynous coral reef fish. Male behaviour assumption is instead purely dependent on attaining social dominance. This is the first example of a vertebrate fully expressing a male behavioural phenotype without current or previous exposure to a functioning testis or testicular products.}, number={1377}, journal={Proceedings of the Royal Society of London. Series B: Biological Sciences}, publisher={The Royal Society}, author={Godwin, John and Crews, David and Warner, Robert R.}, year={1996}, month={Dec}, pages={1683–1688} }
 @article{crews_godwin_hartman_grammer_prediger_shepperd_1996, title={Intrahypothalamic Implantation of Progesterone in Castrated Male Whiptail Lizards (Cnemidophorus inornatus) Elicits Courtship and Copulatory Behavior and Affects Androgen Receptor- and Progesterone Receptor-mRNA Expression in the Brain}, volume={16}, DOI={10.1523/JNEUROSCI.16-22-07347.1996}, abstractNote={A primary tenet of behavioral neuroendocrinology is that gonadal steroid hormones act on limbic nuclei to activate mating behavior in vertebrates. Traditionally, research has focused on the regulation of male-typical sexual behavior by testicular androgens and female-typical sexual behavior by ovarian estrogen and progesterone. Indeed, progesterone generally is regarded as an antiandrogen, acting centrally to inhibit sexual behavior in males. However, experiments with lizards, and more recently with rats, have challenged this paradigm. For example, exogenous progesterone induces mating behavior in some, but not all, castrated male whiptail lizards. The present study determined that implantation of progesterone into the anterior hypothalamus preoptic area of castrated, progesterone-sensitive males completely restored sexual behavior but failed to elicit sexual activity in castrated, progesterone-insensitive males. Further, androgen receptor- and progesterone receptor-mRNA expression in specific brain regions was significantly different in progesterone-sensitive versus progesterone-insensitive animals. Progesterone-sensitive males showed significantly higher relative abundance of androgen receptor-mRNA in the preoptic area, amygdala, and lateral septum, as compared with progesterone-insensitive animals receiving the same treatment. In contrast, progesterone receptor-mRNA abundance was lower in preoptic area of progesterone-sensitive males than in progesterone-insensitive males. No differences were found in the baseline abundance of androgen receptor- or progesterone receptor-mRNA in these nuclei between control groups of progesterone-sensitive and progesterone-insensitive males who were castrated but not implanted. This suggests that progesterone differentially regulates its own receptor as well as androgen receptor in areas of the brain involved in the control of sexual behavior of males and that the nature of this regulation shows individual variability.}, number={22}, journal={Journal of Neuroscience}, author={Crews, D. and Godwin, J. and Hartman, V. and Grammer, M. and Prediger, E. and Shepperd, R.}, year={1996}, month={Nov}, pages={7347–7352} }
 @article{godwin_hartman_grammer_crews_1996, title={Progesterone Inhibits Female-Typical Receptive Behavior and Decreases Hypothalamic Estrogen and Progesterone Receptor Messenger Ribonucleic Acid Levels in Whiptail Lizards (GenusCnemidophorus)}, volume={30}, ISSN={0018-506X}, url={http://dx.doi.org/10.1006/hbeh.1996.0017}, DOI={10.1006/hbeh.1996.0017}, abstractNote={Female-typical sexual behavior in tetrapods is mediated primarily by estrogen and progesterone acting through intracellular receptors at specific sites in the mediobasal hypothalamus. Progesterone exerts both faciliatory and inhibitory actions on female sexual behavior and in well-studied rodent models, the inhibitory actions are exerted through downregulation of progesterone and estrogen receptors. This study examined progesterone effects on both female-typical sexual behavior and hypothalamic estrogen and progesterone receptor mRNA expression (ER- and PR-mRNA) in a sexual and parthenogenetic species of whiptail lizard. Progesterone capsules administered to ovariectomized female Cnemidophorus inornatus and Cnemidophorus uniparens following a receptivity-inducing dosage of estradiol benzoate (EB) strongly inhibited receptive behavior as compared to blank implanted controls. Progesterone capsules administered either before or after an EB injection also strongly downregulated ER- and PR-mRNA abundance in the ventromedial nucleus of the hypothalamus relative to blank implanted controls. The correlated decrease in both EB-induced receptive behavior and ER- and PR-mRNAs following progesterone administration are similar to findings in rats and guinea pigs, suggesting that this is an evolutionarily conserved mechanism in the regulation of female sexual behavior.}, number={2}, journal={Hormones and Behavior}, publisher={Elsevier BV}, author={Godwin, John and Hartman, Vesta and Grammer, Michael and Crews, David}, year={1996}, month={Jun}, pages={138–144} }
 @article{godwin_1995, title={Phylogenetic and Habitat Influences on Mating System Structure in the Humbug Damselfishes (Dascyllus, Pomacentridae)}, volume={57}, number={3}, journal={Bulletin of Marine Science}, author={Godwin, J.R.}, year={1995}, pages={637–652} }
 @article{young_godwin_grammer_gahr_crews_1995, title={Reptilian sex steroid receptors: Amplification, sequence and expression analysis}, volume={55}, ISSN={0960-0760}, url={http://dx.doi.org/10.1016/0960-0760(95)00172-v}, DOI={10.1016/0960-0760(95)00172-v}, abstractNote={Sex steroid hormones secreted by the gonads play a central role in the reproduction of all vertebrates. In addition to direct effects on gametogenesis, sex steroid hormones are important in sexual development, brain organization, and sexual behavior. The actions of sex steroid hormones are mediated primarily by ligand-dependent transcription factors, or receptors which bind to specific sequences of the DNA and alter the transcription rates of nearby genes. We have used the polymerase chain reaction to amplify cDNA fragments of the estrogen receptor, progesterone receptor and androgen receptor from the unisexual whiptail lizard, Cnemidophorus uniparens. The lizard steroid hormone receptors share a high degree of sequence homology to the steroid hormone receptors of other vertebrates. Ribonuclease protection assays demonstrate that both estrogen receptor mRNA and progesterone receptor mRNA are increased in the oviduct during vitellogenesis and after estrogen treatment. This report demonstrates the utility of the polymerase chain reaction to generate species specific probes for comparative molecular studies and provides the first report of cDNA sequences for reptilian steroid hormone receptors.}, number={2}, journal={The Journal of Steroid Biochemistry and Molecular Biology}, publisher={Elsevier BV}, author={Young, Larry J. and Godwin, John and Grammer, Mike and Gahr, Manfred and Crews, David}, year={1995}, month={Nov}, pages={261–269} }
 @article{godwin_crews_1995, title={Sex Differences in Estrogen and Progesterone Receptor Messenger Ribonucleic Acid Regulation in the Brain of Little Striped Whiptail Lizards}, volume={62}, ISSN={0028-3835 1423-0194}, url={http://dx.doi.org/10.1159/000127016}, DOI={10.1159/000127016}, abstractNote={Sex differences in the regulation of steroid hormone receptors in brain areas controlling female- and male-typical sexual behavior may be important in determining sex differences in the display of these behaviors. This study examined sex differences in estrogenic effects on the relative abundance of messenger RNA for estrogen receptor (ER) and progesterone receptor (PR) in discrete brain areas of whiptail lizards, Cnemidophorus inornatus, by in situ hybridization with radiolabeled riboprobes. Gonadectomized females and males received an estradiol benzoate (EB) injection (0.5 microgram) which effectively induces receptive behavior in females; controls received vehicle alone. Sex and regional differences in estrogenic effects on ER- and PR-mRNA abundance were found. Females responded to EB treatment with increases in ER- and PR-mRNA relative abundance in the ventromedial nucleus of the hypothalamus (VMH). Males had similar relative mRNA abundances to females in gonadectomized controls, but did not exhibit increases with EB treatment. EB treatment increased ER-mRNA abundance in the dorsal hypothalamus of females, but not males. ER-mRNA decreases in the lateral septum and PR-mRNA increases in the posterior hypothalamus with hormone treatment were also found, but did not differ by sex. Neither sex nor treatment effects were definitively shown for ER- or PR-mRNA abundance in the anterior hypothalamus-preoptic area. The VMH controls female-typical receptive behavior in this species. Sex differences in the response to estrogen in this nucleus may therefore underlie sex differences in the display of receptive behavior.(ABSTRACT TRUNCATED AT 250 WORDS)}, number={3}, journal={Neuroendocrinology}, publisher={S. Karger AG}, author={Godwin, John and Crews, David}, year={1995}, pages={293–300} }
 @article{godwin_1994, title={Behavioural aspects of protandrous sex change in the anemonefish, Amphiprion melanopus, and endocrine correlates}, volume={48}, ISSN={0003-3472}, url={http://dx.doi.org/10.1006/anbe.1994.1275}, DOI={10.1006/anbe.1994.1275}, abstractNote={Abstract Abstract. Behavioural and endocrine differences between males and females, and during protandrous sex change were characterized in the anemonefish, Amphiprion melanopus. Females are the largest and behaviourally dominant members of social groups, displaying frequent aggression towards their smaller male mates and other smaller non-reproductive individuals. Sex change was stimulated experimentally through female removals in 1989 and 1991. Behavioural samples were taken prior to female removal and from 10 to 45 days after removal in 1989 and 1-20 days after removal in 1991. Sex-changing individuals showed striking increases in aggression within 1 day following female removal. While the frequency of aggressive acts initiated by sex-changing individuals decreased gradually over the 5-, 10- and 20-day samples, it remained significantly elevated over baseline male levels. A decrease in aggression was also observed from 20 to 45 days after female removal in 1989. Presentations of a model intruder to sex-changing individuals at various stages revealed changes to a pattern of territorial defence characteristic of females. Overall aggression increased and the ratio of attacks at the periphery of the territory to those at the centre increased with time after female removal. There was no convincing evidence of a relationship between plasma levels of the five steroids measured and (1) male/female behavioural differences or (2) behavioural changes with sex change.}, number={3}, journal={Animal Behaviour}, publisher={Elsevier BV}, author={Godwin, John}, year={1994}, month={Sep}, pages={551–567} }
 @article{godwin_1994, title={Historical aspects of protandrous sex change in the anemonefishAmphiprion melanopus(Pomacentridae, Teleostei)}, volume={232}, ISSN={0952-8369 1469-7998}, url={http://dx.doi.org/10.1111/j.1469-7998.1994.tb01569.x}, DOI={10.1111/j.1469-7998.1994.tb01569.x}, abstractNote={Gonadal structure and cellular composition were examined in juveniles, males and females of the protandric hermaphrodite, Amphiprion melanopus. Functional sex change was experimentally induced in the field and gonad structure was histologically examined both qualitatively and quantitatively at 10, 20, 30 and 45 days after its initiation. Juvenile gonads consist primarily of immature ovarian tissue. Functional male gonads are ovotestes with co‐existing mature spermatogenic tissue and immature ovarian tissue, while females possess only ovarian tissue. The initiation of sex change is marked by a rapid maturation of spermatogenic tissue and proliferation of putative oogonia. Gonads were essentially female by 20 days into sex change, but evidence of mature female function (marked by the initiation of vitellogenesis) was not observed until 45 days. Considerable variation between individuals was seen in quantitative measures of gonadal change in the early stages of sex change, but not in later stages. Progress in sex change as indicated by histological indicators was, however, consistent within stages. Duet systems for gamete transport changed from the male to the female form after all male tissue had been replaced.}, number={2}, journal={Journal of Zoology}, publisher={Wiley}, author={Godwin, John}, year={1994}, month={Feb}, pages={199–213} }
 @article{godwin_thomas_1993, title={Sex Change and Steroid Profiles in the Protandrous Anemonefish Amphiprion melanopus (Pomacentridae, Teleostei)}, volume={91}, ISSN={0016-6480}, url={http://dx.doi.org/10.1006/gcen.1993.1114}, DOI={10.1006/gcen.1993.1114}, abstractNote={Plasma profiles of several gonadal steroids and cortisol were examined in a field population of the protandrous, sex-changing anemonefish Amphiprion melanopus to elucidate potential roles of these hormones in gonadal sex change. Sex change was experimentally induced in males by removal of their dominant female pair mates. These sex-changing males were captured and sampled at 5, 10, or 20 days after female removal. Unmanipulated males and females were also sampled. Males had higher plasma levels of 11-ketotestosterone (11-KT) than did females, but had lower levels of androstenedione (Ad), testosterone (T), and estradiol-17 beta (E2). The three androgens showed decreases from male levels at 10 days, then an increasing trend at 20 days after female removal. E2 levels exhibited no changes from male levels until 20 days, when a significant increase over male levels was observed. Mature females had higher levels of Ad, T, and E2 than the 20-day treatment group, indicating that these steroids continue to rise after Day 20. The results support hypothesized roles for androgens in male function and E2 in female function in A. melanopus. However, E2 increases lagged behind oogonial proliferation, arguing against an influence of this steroid in the initiation of female function. Cortisol levels did not differ between males and females, but exhibited an increase during sex change, peaking at 20 days.}, number={2}, journal={General and Comparative Endocrinology}, publisher={Elsevier BV}, author={Godwin, John R. and Thomas, Peter}, year={1993}, month={Aug}, pages={144–157} }
 @article{godwin_fautin_1992, title={Defense of Host Actinians by Anemonefishes}, volume={1992}, ISSN={0045-8511}, url={http://dx.doi.org/10.2307/1446171}, DOI={10.2307/1446171}, number={3}, journal={Copeia}, publisher={JSTOR}, author={Godwin, John and Fautin, Daphne G.}, year={1992}, month={Aug}, pages={902} }
 @article{godwin_kosaki_1989, title={Reef fish assemblages on submerged lava flows of three different ages}, volume={43}, number={4}, journal={Pacific Science}, author={Godwin, J.R. and Kosaki, R.K.}, year={1989}, pages={289–301} }