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 通过基因分析，了解产生新的 物种及其随之而来的形态和行为差异。在这里我们 建议研究果蝇亚群中的两个物种， 一种包括最近发现的进化分化的D.santomea(a 新发现的岛屿特有种)，及其姊妹种--雅库巴，以及另一种 独立的姊妹对毛氏盘藻/盘尾盘藻。我们提出以下要求 问题。 1.桑多美斑潜蝇生殖隔离的形式和程度是什么 和D.Yakuba？我们将对性、受精后和“后交配”进行量化， 这些研究对于我们的遗传分析是必要的。 这些特征，但也将使我们能够比较这种进化的分歧 在同一组中有两个独立的物种形成事件，所有这些事件都发生了 几乎在同一时间。 2.性隔离、杂交性雄性不育和 这两个物种在色素沉着方面有显著差异吗？这些问题 将通过数量性状基因座(QTL)作图来回答，这是一种更 比我们过去使用的粗略的基于突变的图谱更精确。这个 获得有关染色体的数量、效应和位置的信息 影响物种形成和特征差异的地区将有助于回答 长期存在的进化遗传学问题。 3.在圣多美/雅库巴有“增援”活动吗？这些物种有 圣多美岛上重叠的山脉，让我们表演了一场罕见的 “强化”测试：自然选择可以 增加物种之间在其区域内的性别隔离程度 重叠。 4.拟石杉与石杉的性隔离的遗传基础是什么？ 毛瑞蒂亚纳？对性隔离的遗传学几乎一无所知 这两个人的分歧也涉及岛屿殖民。QTL定位将 揭示涉及到的染色体区域的数量、效应和位置 雄性、雌性和缩短种间的性隔离 交配抑制基因流动。 我们的结果将使我们能够比较独立但 密切相关的类群，最终可能有助于定位和分离 “物种形成”和“适应”基因，并可能与理解 其他动物群中物种的起源，包括人类。

DESCRIPTION (provided by applicant): The long-term goal of our laboratory is to understand, through genetic analysis, the evolutionary forces producing new species and the attendant differences in their morphology and behavior. Here we propose to study two pair of species in the Drosophila melanogaster subgroup, one comprising a recently discovered evolutionary divergence D. santomea (a newly-found island endemic), and its sister species D. yakuba; and the other the independent sister pair D. mauritiana/D.simulans. We ask the following questions. 1. What are the forms and degrees of reproductive isolation between D. santomea and D. yakuba? We will quantify sexual, postzygotic, and "postmating, prezygotic" isolation. These studies are necessary for our genetic analysis of these traits, but will also allow us to compare this evolutionary divergence with two independent speciation events in the same group, all of which occurred at about the same time. 2. What are the genetic bases of sexual isolation, hybrid male sterility, and a striking difference in pigmentation between these two species? These questions will be answered with quantitative-trait-locus (QTL) mapping, a method more precise than the crude mutant-based mapping we have used in the past. The acquired information about the numbers, effects, and locations of chromosome regions affecting speciation and character differences will help answer long-standing questions of evolutionary genetics. 3. Does "reinforcement" operate in D. santomea/yakuba? These species have overlapping ranges on the island of Sao Tome, allowing us to perform a rare test for "reinforcement": the controversial idea that natural selection can increase the degree of sexual isolation between species in their area of overlap. 4. What is the genetic basis of sexual isolation between D. simulans and D. mauritiana? Almost nothing is known about the genetics of sexual isolation in this pair, whose divergence also involved island colonization. QTL mapping will reveal the numbers, effects, and locations of chromosomes regions involved in sexual isolation of males, of females, and of shortened interspecific copulation inhibiting gene flow. Our results will allow us to compare patterns of speciation in independent but closely related taxa, may eventually facilitate the location and isolation of "speciation" and "adaptation" genes, and may be relevant to understanding the origin of species in other animal groups, including humans.