Our research takes advantage of the variation present in species radiations and in natural hybrid zones to identify traits and regions of the genome that are associated with reproductive isolation and adaptation. Specifically, we use genomic tools such as DNA metabarcoding and whole genome sequencing to understand (1) the evolution of adaptive traits, like coloration, and their role in speciation, (2) the role of symbiotic interactions in diversification, and (3) the genomic architecture of speciation and role of the sex chromosomes.
Coloration and diversificationPigmentation underlies diversification in many vertebrate systems. We are using colorful wood warblers as a study system to investigate the genetic basis of plumage traits. Some of our recent work suggests the same genes have been recruited repeatedly in the evolution of divergent phenotypes across Setophaga warblers. Further, our research provides the first evidence of lateral transfer of a carotenoid processing gene (BCO2) in vertebrates.
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Gut microbiome structure and its relationship with host divergenceSymbiotic gut microbiota (GM) take part in important physiological functions and impact host health, immunity, and behavior. Thus there are significant implications of GM structure for host species, however, the role of the GM in diversification has been largely under-explored. We have developing the wood warbler system to investigate the relationship between host divergence and GM structure. This project takes advantage of the broadly overlapping breeding ranges among warbler species and of natural hybrid zones between species pairs that differ in their extent of genomic divergence.
Our work adds to the growing body of evidence suggesting weak signatures of GM differentiation between avian species, a pattern discordant from that found in terrestrial mammals. This suggests environmental factors, like habitat, seasonality, and diet might play a stronger role than genetics in shaping GM structure within bird species. To explore this, we are doing field experiments to test how diet manipulation might affect the GM in breeding birds that nest in nest boxes. |
Hybrid zones as "windows" on evolutionary processWe are interested in understanding the genetic architecture of adaptive traits and of reproductive isolation. We use approaches that take advantage of variation in natural hybrid zones to identify genomic regions under selection and link important phenotypes to underlying genotypes.
We use whole genome sequencing of Vermivora warblers and their hybrids to study inheritance of plumage traits. Our work supports simple Mendelian inheritance of throat and mask coloration associated with separate, but tightly linked, loci upstream of the ASIP gene. Our research also shows inheritance of carotenoid pigmentation in hybrids is not as straightforward, suggesting this trait has a complex genetic basis and is likely influenced by environmental factors. We also use genomic data identify candidate loci involved in reproductive isolation in primates. Notably, our work shows these loci are disproportionately represented on the X chromosome in howler monkeys and these regions may be shared with hominins, implicating parallels in the evolution of reproductive isolation across primates. |