@article{delorenzo_debrock_baez_ciccotto_peterson_stull_roberts_roberts_powder_2022, title={Morphometric and Genetic Description of Trophic Adaptations in Cichlid Fishes}, volume={11}, ISSN={["2079-7737"]}, url={https://www.mdpi.com/2079-7737/11/8/1165}, DOI={10.3390/biology11081165}, abstractNote={Since Darwin, biologists have sought to understand the evolution and origins of phenotypic adaptations. The skull is particularly diverse due to intense natural selection on feeding biomechanics. We investigated the genetic and molecular origins of trophic adaptation using Lake Malawi cichlids, which have undergone an exemplary evolutionary radiation. We analyzed morphological differences in the lateral and ventral head shape among an insectivore that eats by suction feeding, an obligate biting herbivore, and their F2 hybrids. We identified variation in a series of morphological traits—including mandible width, mandible length, and buccal length—that directly affect feeding kinematics and function. Using quantitative trait loci (QTL) mapping, we found that many genes of small effects influence these craniofacial adaptations. Intervals for some traits were enriched in genes related to potassium transport and sensory systems, the latter suggesting co-evolution of feeding structures and sensory adaptations for foraging. Despite these indications of co-evolution of structures, morphological traits did not show covariation. Furthermore, phenotypes largely mapped to distinct genetic intervals, suggesting that a common genetic basis does not generate coordinated changes in shape. Together, these suggest that craniofacial traits are mostly inherited as separate modules, which confers a high potential for the evolution of morphological diversity. Though these traits are not restricted by genetic pleiotropy, functional demands of feeding and sensory structures likely introduce constraints on variation. In all, we provide insights into the quantitative genetic basis of trophic adaptation, identify mechanisms that influence the direction of morphological evolution, and provide molecular inroads to craniofacial variation.}, number={8}, journal={BIOLOGY-BASEL}, author={DeLorenzo, Leah and DeBrock, Victoria and Baez, Aldo Carmona and Ciccotto, Patrick J. and Peterson, Erin N. and Stull, Clare and Roberts, Natalie B. and Roberts, Reade B. and Powder, Kara E.}, year={2022}, month={Aug} }
 @article{moore_ciccotto_peterson_lamm_albertson_roberts_2022, title={Polygenic sex determination produces modular sex polymorphism in an African cichlid fish}, volume={119}, ISSN={["1091-6490"]}, DOI={10.1073/pnas.2118574119}, abstractNote={Significance
          Sex differences in traits can occur when those traits are modified by genetic factors inherited on sex chromosomes. We investigated how sex differences emerge in a species with more than one set of sex chromosomes, measuring a variety of morphological, physiological, and behavioral traits. Rather than exhibiting sexual dimorphism associated with primary sex, the species has higher-order sexual polymorphism in secondary sexual characteristics or more than two phenotypic sexes. Variation in secondary sexual characteristics is modular, involving the interplay of sex-linked and sex-limited traits. Our findings provide implications for how sex determination systems and whole-organism fitness traits coevolve, including that significant creation or loss of variation in diverse traits can occur during transitions among sex chromosome systems.}, number={14}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Moore, Emily C. and Ciccotto, Patrick J. and Peterson, Erin N. and Lamm, Melissa S. and Albertson, R. Craig and Roberts, Reade B.}, year={2022}, month={Apr} }
 @article{peterson_cline_moore_roberts_roberts_2017, title={Genetic sex determination in Astatotilapia calliptera, a prototype species for the Lake Malawi cichlid radiation}, volume={104}, ISSN={["1432-1904"]}, DOI={10.1007/s00114-017-1462-8}, abstractNote={East African cichlids display extensive variation in sex determination systems. The species Astatotilapia calliptera is one of the few cichlids that reside both in Lake Malawi and in surrounding waterways. A. calliptera is of interest in evolutionary studies as a putative immediate outgroup species for the Lake Malawi species flock and possibly as a prototype ancestor-like species for the radiation. Here, we use linkage mapping to test association of sex in A. calliptera with loci that have been previously associated with genetic sex determination in East African cichlid species. We identify a male heterogametic XY system segregating at linkage group (LG) 7 in an A. calliptera line that originated from Lake Malawi, at a locus previously shown to act as an XY sex determination system in multiple species of Lake Malawi cichlids. Significant association of genetic markers and sex produce a broad genetic interval of approximately 26 megabases (Mb) using the Nile tilapia genome to orient markers; however, we note that the marker with the strongest association with sex is near a gene that acts as a master sex determiner in other fish species. We demonstrate that alleles of the marker are perfectly associated with sex in Metriaclima mbenjii, a species from the rock-dwelling clade of Lake Malawi. While we do not rule out the possibility of other sex determination loci in A. calliptera, this study provides a foundation for fine mapping of the cichlid sex determination gene on LG7 and evolutionary context regarding the origin and persistence of the LG7 XY across diverse, rapidly evolving lineages.}, number={5-6}, journal={SCIENCE OF NATURE}, author={Peterson, Erin N. and Cline, Maggie E. and Moore, Emily C. and Roberts, Natalie B. and Roberts, Reade B.}, year={2017}, month={Jun} }