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

当种群进化出不相容的等位基因，导致致死或致死时， 在隔离的种群之间杂交后代的不育性。了解的演变 物种之间的生殖隔离需要基因的功能特征 这会导致基因交换的障碍，并决定它们如何杀死或绝育 混血儿物种形成生物学中两种引人注目的模式是杂种的早期积累 具有X和Y染色体的动物分类群的雄性不育（Halfman规则）， X染色体上杂种不育因子的富集（大X效应）。 因此，XY物种（如哺乳动物和果蝇）的物种形成与 导致种间杂种雄性不育的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 没有足够的经验数据来检验这些假设。的长期目标 这项研究的目的是确定以前未知的X连锁基因， 果蝇近缘种之间的杂种雄性不育，并表征 这些基因破坏精子发生的机制。这些目标将 增加我们对物种形成、进化、 基因和基因组的差异，以及精子发生的发育过程。 拟议中的研究将使用遗传和转基因方法来识别，验证， 研究X连锁杂种不育基因。全基因组基因表达和 细胞学分析将确定这些基因是如何破坏杂种精子发生的; 人口和进化基因组资源将用于确定 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.