Demographics and phylogeography of hybrid speciation

描述（由申请人提供）：拟议研究的目标是更好地了解向日葵属杂交物种形成的人口统计学。通过两个相同的亲本物种之间的杂交，形成了三个同源倍体物种。据认为，杂交物种形成向日葵可能已经促进了创始人事件，但基本上是什么都不知道的人口学的杂交物种在这些或其他二倍体杂交种。具体目标是：1）使用聚结方法和分布在整个基因组中的许多位点来估计杂交物种中的祖先有效种群大小和种群增长率，以确定它们是否符合创始者事件物种形成模型的期望;（二）确定杂交种和亲本物种之间的渐渗水平，并测试渐渗率与不同的选择力和染色体相关的假设。在不同的基因组区域的重排; 3）进行亲本物种的地理学研究，以测试的假设，野牛引入到北美有助于杂交物种的增加分散和隔离在独特的栖息地的潜力;和4）进行杂交物种的地理学研究，以测试范围扩大。

DESCRIPTION (provided by applicant): The goal of the proposed research is to gain a better understanding of the demographics of hybrid speciation in the sunflower genus Helianthus. Three homoploid species were formed via hybridization between the same two parental species. It is thought that hybrid speciation in Helianthus may have been facilitated by founder events, but essentially nothing is known about the demography of hybrid speciation in these or other diploid hybrid species. The specific aims are to 1) use coalescent methods and many loci spread throughout the genome to estimate ancestral effective population sizes and population growth rates in the hybrid species to determine if they conform to expectations of a founder event speciation model; 2) determine levels of introgression between hybrid and parental species and test the hypotheses that introgression rates are correlated with varying selective forces and chromosomal rearrangements in various genomic regions; 3) perform phylogeographic studies of the parental species to test the hypothesis that the introduction of bison to North America contributed to hybrid speciation by increasing dispersal and the potential for isolation in unique habitats; and 4) perform phylogeographic studies of hybrid species to test for range expansion.