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

物种是生物多样性的基本单位，但对自然界物种的识别，以及对这些物种形成的方式和原因的理解，仍然是重大的科学挑战。本研究的目的是确定物种边界，解释物种分化的原因，测试物种之间生殖隔离的存在，并研究自然选择在物种形成中的作用。通过在一组处于不同分化阶段的密切相关物种中解决这些问题，这项研究将包括对爬行动物物种和物种形成的最详细的分析。这项工作的结果将为了解物种和有效的生物多样性保护管理提供新的见解。这项工作的发现将在堪萨斯大学自然历史博物馆以展览的形式公开分享，这将吸引学龄游客和他们的教师，以及通过两个受公众和所有年龄段学生欢迎的在线资源。这项工作将调查对现代合成时代观点的挑战，该观点认为物种是表型独特的，生殖隔离的种群，由于创始人事件，遗传漂变和相关现象而在地理隔离中分化。首先，通过在一个高度可变的物种复合体中量化基因组、表型和生态变异，这项工作将测试最近的物种形成事件是否被传统的分类学方法所忽视。其次，景观遗传分析将用于测试生物地理和生态过程对物种分化的贡献。第三，多代实验杂交将测试内在的生殖隔离是否在物种形成过程中相对较早地进化，并符合一般规则。最后，第四，利用从自然界中采样的个体和已知谱系的个体的基因组序列数据，这项工作将测试物种之间的初始差异是否主要是由自然选择作用于有限数量的位点或基因组区域造成的。这项工作将在一个高度可变的物种综合体中研究这些主题，包括物种形成过程的各个阶段的种群。这里提出的工作将需要对爬行动物进行最详细和综合的分析，并将导致新的实验室模式生物的发展，通过连锁图谱组装的第一个爬行动物基因组，以及对遗传能力和表型特征的基因组基础的首次估计，这对爬行动物的系统研究很重要。

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.