Bridging observational, experimental and genomic insights on species and speciation through comparative analyses in a new vertebrate model system

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Species are the fundamental units of biological diversity, but the identification of species in nature, and understanding of how and why these species form, remain significant scientific challenges. The goals of this research are to identify species boundaries, explain why species diverged, test for the presence of reproductive isolation between species, and investigate the role of natural selection in speciation. By addressing each of these objectives in a group of closely related species at varying stages of divergence, this research will involve the most detailed analyses of species and speciation ever conducted in a reptile. The results of this work will provide new insights that are central to understanding species and to effective conservation management of biological diversity. Discoveries resulting from this work will be shared publicly in the form of an exhibit at the University of Kansas Natural History Museum that will engage school aged visitors and their instructors as well as via two online resources that are popular with the general public and students of all ages. This work will investigate challenges to the modern synthesis-era view that species are phenotypically distinct and reproductively isolated populations that diverged in geographic isolation due to founder events, genetic drift and related phenomena. First, by quantifying genomic, phenotypic, and ecological variation across a highly variable species complex, this work will test if recent speciation events have been overlooked by traditional taxonomic methods. Second, landscape genetic analyses will be used to test the contribution of biogeographic and ecological processes to species divergence. Third, multi-generational experimental crosses will test if intrinsic reproductive isolation evolves relatively early in the speciation process, and in accordance with general rules. Finally, fourth, using mapped genomic sequence data from individuals sampled in nature and individuals with known pedigrees, this work will test if initial divergence between species results largely from natural selection acting on a limited number of loci or genomic regions. This work will investigate each of these topics in a highly variable species complex that includes populations at various stages of the speciation process. The work proposed here will entail the most detailed and integrative analyses ever conducted in a reptile and will result in development of a new laboratory model organism, the first reptile genome assembled via linkage mapping, and the first estimates of heritability and the genomic basis for phenotypic traits important to systematic studies of reptiles.