Determining population structure and hybridization for two iris species

Identifying processes that promote or limit gene flow can help define the ecological and evolutionary history of a species. Furthermore, defining those factors that make up “species boundaries” can provide a definition of the independent evolutionary trajectories of related taxa. For many species, the historic processes that account for their distribution of genetic variation remain unresolved. In this study, we examine the geographic distribution of genetic diversity for two species of Louisiana Irises, Iris brevicaulis and Iris fulva. Specifically, we asked how populations are structured and if population structure coincides with potential barriers to gene flow. We also asked whether there is evidence of hybridization between these two species outside Louisiana hybrid zones. We used a genotyping-by-sequencing approach and sampled a large number of single nucleotide polymorphisms across these species' genomes. Two different population assignment methods were used to resolve population ...

阐明促进或限制基因流（gene flow）的过程，有助于解析物种的生态与演化历史。此外，明确构成“物种边界（species boundaries）”的关键因子，可为相关类群（taxa）的独立演化轨迹提供界定依据。针对诸多物种而言，解释其遗传变异分布格局的历史演化过程仍未明确。本研究以两种路易斯安那鸢尾（Louisiana Irises）——短茎鸢尾（Iris brevicaulis）与褐黄鸢尾（Iris fulva）为研究对象，解析其遗传多样性的地理分布格局。具体而言，本研究旨在解答两大科学问题：其一，种群的遗传结构具有何种特征？其二，种群结构是否与潜在的基因流屏障相契合？此外，本研究还探究了路易斯安那杂交带以外区域是否存在这两个物种间的杂交证据。本研究采用测序基因分型（genotyping-by-sequencing）技术，在两个物种的全基因组范围内获取了海量单核苷酸多态性（Single Nucleotide Polymorphisms, SNPs）位点数据。本研究采用两种不同的种群归属分析方法，以解析种群……