Investigating the special role of sex chromosomes in speciation: discovering the molecular identities, functions, and evolutionary histories of X-linked hybrid male sterility genes in Drosophila

当种群进化出导致致命性或致命性的不相容等位基因时，新物种就会出现 隔离种群间杂交后代的不育性。了解以下方面的演变 物种间的生殖隔离需要基因的功能特征 导致基因交换和决定它们如何杀死或绝育的障碍 混血儿。物种形成生物学中的两个显著模式是杂交的早期积累 具有X和Y染色体的动物类群中的雄性不育(霍尔丹法则)，以及 杂交不育因子在X染色体上的浓缩(大X效应)。 因此，哺乳动物和果蝇等XY物种的物种形成与 在种间杂交中导致雄性不育的X连锁等位基因的快速进化。 已经提出了多种进化模型来解释这两种模式，但 没有足够的实证数据来检验这些假设。的长期目标 这项拟议的研究是为了识别以前未知的X连锁基因，这些基因会导致 果蝇近缘种间杂种雄性不育及其特性 这些基因扰乱精子发生的机制。这些目标将 增加我们对物种形成、进化的生物过程的理解 基因和基因组的分化，以及精子发生的发育过程。 这项拟议的研究将使用遗传和转基因方法来识别、验证 并研究X连锁杂交不育基因。全基因组的基因表达和 细胞学分析将确定这些基因如何干扰杂交后代的精子发生； 种群和进化基因组资源将被用来确定 这些基因的进化史。

New species arise when populations evolve incompatible alleles that lead to lethality or sterility in hybrid offspring between isolated populations. Understanding the evolution of reproductive isolation between species requires functional characterization of the genes that cause barriers to genetic exchange and determining how they kill or sterilize hybrids. Two striking patterns in speciation biology are the early accumulation of hybrid male sterility in animal taxa with X and Y chromosomes (Haldane's Rule), and the enrichment of hybrid sterility factors on the X chromosome (the large X-effect). Speciation in XY species such as mammals and fruit flies is therefore associated with the rapid evolution of X-linked alleles that cause male sterility in interspecific hybrids. Multiple evolutionary models have been proposed to explain both these patterns, but there is insufficient empirical data to test these hypotheses. The long-term objectives of the proposed research are to identify previously unknown X-linked genes that cause hybrid male sterility between closely related species of Drosophila, and to characterize the mechanisms by which these genes disrupt spermatogenesis. These objectives will increase our understanding of the biological processes of speciation, evolutionary divergence in genes and genomes, and the developmental process of spermatogenesis. The proposed research will use genetic and transgenic approaches to identify, verify, and investigate X-linked hybrid sterility genes. Genome-wide gene expression and cytological analyses will determine how these genes disrupt spermatogenesis in hybrids; and population and evolutionary genomic resources will be used to determine the evolutionary history of these genes.