Genetic Basis of Posterior Lobe Evolution in Drosophila

果蝇后叶进化的遗传基础

• 批准号: 6584300
• 负责人: BARRY WILLIAMS
• 金额: $ 4.16万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-23 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6584300
• 关键词: Drosophilidae; biochemical evolution; cell morphology; gene complementation; gene expression; genetic mapping; genetic polymorphism; genetic regulatory element; linkage disequilibriums; male; molecular genetics; neurohypophysis; population genetics; postdoctoral investigator; quantitative trait loci; reproductive development; sex determination

DESCRIPTION (provided by applicant): The molecular basis of morphological evolution has been a long standing topic of interest in evolutionary biology, but a mechanistic understanding of this process has been elusive. The male genital posterior lobe exhibits substantial variation in size between the recently diverged (0.6 - 0.9 million years) species of Drosophila simulans and D.mauritiana, and there is a large amount of background work describing the genetic architecture of this trait. Several QTL have already been localized to narrow chromosomal intervals, have largely additive effects, and the direction of these effects are consistent across loci, which suggests a history of strong directional selection. The goals of the proposed research are to: 1) identify at least one gene that explains a significant portion of the interspecific variation 2) identify the cis-regulatory sequence for that gene, 3) characterize the pattern of gene expression in each species, and 4) determine the molecular basis of functional sequence divergence at that locus. I will begin idenfication of the target gene by crossing males of both D. simulans and D. mauritiana to deficiency stocks and alleles of genes from D. -melanogaster, for a subset of QTL intervals, to identify loci that fail to complement phentypic recovery of a hybrid phenotype. If this method fails to identify any target loci, I will create congenic lines to use linkage disequilibrium mapping and potentially p-element mediated site specific recombination to localize a single target gene. Once a gene has been identified I will idenfity the cis-regulatory element that drives it's expression in the genital disc and examine variation in gene expression between the three species to determine if cis-regulatory evolution is responsible for the observed differentiation. Finally, I will use population genetic methods to identify specific regions in the protein coding and regulatory sequences that have evolved under positive selection.

描述（由申请人提供）：形态进化的分子基础一直是进化生物学中的一个长期存在的感兴趣的话题，但对这一过程的机制理解一直是难以捉摸的。雄性生殖器后叶在最近分化（0.6 - 0.9百万年）的拟果蝇和D.mauritiana物种之间表现出相当大的变化，并且有大量的背景工作描述了这一特征的遗传结构。几个QTL已经定位到狭窄的染色体间隔，具有很大的加性效应，并且这些效应的方向在基因座之间是一致的，这表明了强定向选择的历史。该研究的目标是：1）确定至少一个基因，解释种间变异的重要部分2）确定该基因的顺式调控序列，3）表征每个物种的基因表达模式，以及4）确定该位点功能序列差异的分子基础。我将开始通过杂交两个D的雄性来验证目标基因。simulans和D. mauritiana与缺素群体的遗传关系及来自D. - 黑腹，对于QTL区间的子集，以鉴定不能补充杂种表型的表型恢复的基因座。如果这种方法不能识别任何靶基因座，我将创建同源系，使用连锁不平衡作图和潜在的p元件介导的位点特异性重组来定位单个靶基因。一旦一个基因被确定，我将分析驱动它在生殖盘中表达的顺式调节元件，并检查三个物种之间基因表达的变化，以确定顺式调节进化是否是观察到的分化的原因。最后，我将使用群体遗传学的方法来确定特定区域的蛋白质编码和调节序列，已经在积极的选择。