Demographics and phylogeography of hybrid speciation

拟议研究的目标是更好地了解混合物种形成的人口统计学特征。 向日葵属中的一种。通过杂交形成了三个同倍体物种 相同的两个亲代物种。据认为，向日葵的杂交物种形成可能是由 创始人事件，但基本上对这些或其他混合物种的人口统计学一无所知 二倍体杂交种。具体的目标是1)使用联合的方法和分布在各地的多个基因座 用来估计杂交后代有效种群大小和种群增长率的基因组 物种以确定它们是否符合创始人事件物种形成模型的期望；2)确定 杂交种和亲本物种之间的渗入水平，并检验渗入速率的假设 与不同基因组区域的不同选择力和染色体重排有关；3) 对亲本物种进行系统地理研究，以检验引进野牛 到北美通过增加扩散和隔离的可能性促进了杂交物种的形成 独特的栖息地；以及4)对杂交物种进行系统地理研究，以测试范围的扩大。

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.