Genetic Basis of Species Differences in Drosophila

描述（申请人提供）：我们实验室的长期目标是通过遗传分析了解产生新物种和物种在行为和形态特征上差异的进化力量，以确定参与这种差异的基因，并最终确定物种形成遗传学中是否存在一般模式。我们建议研究这些问题，在两对最近分歧的姐妹种果蝇亚组。我们的具体问题如下： 1. D.杂种雄性不育的遗传基础及D. santomea和D.日式料理？这些物种表现出强烈的性隔离和杂交雄性不育，以及腹部色素沉着和雄性求爱歌曲的强烈差异。我们建议使用精细结构的分子定位，以获得一个小的候选基因影响色素沉着和杂交不育，以及初始的全基因组QTL定位研究种间差异的男性交配歌，可能发挥作用，在性隔离。 2.哪些基因导致了D. simulans和D.毛里求斯？我们的QTL定位这两个物种之间的性隔离揭示了几个小区域的基因组影响配偶歧视。我们建议本地化的“性隔离”基因更准确地在两性使用精细结构遗传作图。 3.物种间允许有多少基因渗入？我们建议，以确定有多少不同进化的物种的基因组之间的混合是允许的，通过构建实验室的“杂交群”对密切相关的物种之间，并遵循分子标记的染色体片段，诊断形态特征，和性隔离的演变了几年。 4.如何解释“杂交区”的异常和野生杂交种的遗传组成？在圣托姆岛上发现的自然产生的杂交种很特别：它们都是雄性，所有的F1杂交种都有一个D. santomea母亲，几乎所有的这些都发生在高海拔地区以外的范围内的任何一个父母种。我们将进行耐受性和偏好的实验室研究，以了解这些异常。我们的研究结果可能与了解其他动物群体（包括人类）的物种起源有关。

DESCRIPTION (provided by applicant): The long-term goals of our laboratory are to understand though genetic analysis the evolutionary forces producing new species and species differences in behavioral and morphological traits, to identify the genes involved in such differences and, ultimately, to determine if there are general patterns in the genetics of speciation. We propose to study these questions in two pairs of recently-diverged sister species in the Drosophila melanogaster subgroup. Our specific questions are the following: 1. What are genetic bases of hybrid male sterility and morphological and behavioral differences between D. santomea and D. yakuba? These species show strong sexual isolation and hybrid male sterility, as well as strong differences in abdominal pigmentation and male courtship song. We propose to use fine-structure molecular mapping to derive a small set of candidate genes affecting pigmentation and hybrid sterility, as well as an initial genome-wide QTL mapping study of an interspecific difference in male mating song that may play a role in sexual isolation. 2. What are the genes responsible for sexual isolation between D. simulans and D. mauritiana? Our QTL mapping of sexual isolation between these two species has revealed several small regions of the genome affecting mate discrimination. We propose to localize "sexual isolation" genes more accurately in both sexes using fine-structure genetic mapping. 3. How much introgression is permissible among species? We propose to determine how much mixing between separately-evolved species' genomes is permissible by constructing laboratory 'hybrid swarms' between pairs of closely-related species, and following the evolution of molecularly marked chromosome segments, diagnostic morphological traits, and sexual isolation over several years. 4. What explains anomalies in the "hybrid zone" and genetic composition of hybrids in the wild? Naturally- occurring hybrids found on Sao Tome Island are peculiar: they are all male, all F1 hybrids having a D. santomea mother, and nearly all of them occur at high altitude outside the range of either parental species. We will perform laboratory studies of tolerance and preference to understand these anomalies. Our results may be relevant to understanding the origin of species in other animal groups, including humans.