Genomics of complex speciation between Drosophila simulans and D. mauritiana

描述（由申请人提供）：本文提出的工作将整合分歧群体基因组学和高分辨率遗传学，以剖析毛里求斯果蝇及其姐妹物种D. simulans。自25万年前分裂以来，这两个物种在杂交的两个方向上都进化出了完全的杂交雄性不育，但也有明显的证据表明最近与基因流的二次接触（杂交雌性是可育的）。该项目的目标是获得一个全面的全基因组分析的自然选择和基因流之间的这些部分繁殖隔离的物种，是由一个精细的全基因组杂交不亲和因子的地图。该项目预计目前正在开发的大规模数据集：来自10个毛里求斯果蝇品系和20个D.模拟。该项目有两个相辅相成的组成部分。首先，新的计算和统计推断方法将开发用于物种趋异的全基因组进化分析。第二，利用新开发的功能遗传资源构建高分辨率的D. simulans的遗传因素，导致杂种不亲和性，否则D. mauritiana基因组背景;这些因子中的2-4个将作为分子鉴定和功能表征的目标。这两个组成部分将被整合到：（1）测试基因组的不相容区域是否富含阳性选择的特征和/或显示种间基因流动的倾向降低;（2）确定为什么，以及物理基因组的程度，X染色体在动物物种形成中起着看似特殊的作用。

DESCRIPTION (provided by applicant): The work proposed here will integrate divergence population genomics and high-resolution genetics to dissect the historical and functional aspects of complex speciation between Drosophila mauritiana and its sister species, D. simulans. Since splitting ~250,000 years ago the two species have evolved complete hybrid male sterility in both directions of the cross and yet show clear evidence for recent secondary contact with gene flow (hybrid females are fertile). The goal of this project is to obtain a comprehensive genome-wide analysis of natural selection and gene flow between these partially reproductively isolated species that is informed by a fine-scale genome-wide map of hybrid incompatibility factors. The project anticipates a massive dataset currently in development: high-coverage whole-genome next-generation resequence data from 10 lines of Drosophila mauritiana and 20 lines of D. simulans. The project has two complementary components. First, novel computational and statistical inference methods will be developed for whole-genome evolutionary analysis of species divergence. Second, newly developed functional genetic resources will be used to construct a high-resolution genome-wide map of D. simulans genetic factors that cause hybrid incompatibilities in an otherwise D. mauritiana genomic background; 2-4 of these factors will be targeted for molecular identification and functional characterization. The two components will be integrated to: (1) test if incompatible regions of the genome are enriched for signatures of positive selection and/or show reduced propensity for interspecific gene flow; and (2) determine why, and the physical genomic extent to which, the X chromosome plays a seemingly special role in animal speciation.