Comparative Genomics of Seminal Fluid Proteins

附属腺蛋白是精液的重要组成部分，影响女性生理和男性健康。许多Acps似乎是在积极的选择，潜在的驱动性冲突，因此是理想的候选人研究共同进化过程。然而，快速的氨基酸取代可能使得仅使用核苷酸序列数据难以鉴定趋异的直系同源物。因此，需要更有针对性的方法来正确识别Acps，即使是在具有完整基因组的物种中。在本研究中，我拟建立四个果蝇附腺特异cDNA文库，以鉴定果蝇sechellia，D。mauritiana、毛叶杜父鱼D. yakuba和D.米兰达，然后我将注释这些基因，并使用D。米兰达Acps来确定其近亲D.伪暗将这些数据与D. melanogaster和D. simulans将产生总共七个物种，然后我将使用最大似然拟合进化模型的分歧数据，以表征选择压力影响这七个物种的精液蛋白质的进化。被鉴定为具有过量氨基酸取代的位点将是阳性选择证据的强有力候选者。这些模型的参数化使用七个物种将提供很好的力量来检测作用于特定谱系或特定功能类基因的进化力量。最后，我将使用转基因D.表达异特异性附属腺蛋白的黑腹果蝇。

Accessory gland proteins (Acps) are important components of seminal fluid, influencing female physiology and affecting male fitness. Many Acps appear to be under positive selection, potentially driven by sexual conflict and are thus ideal candidates to study coevolutionary process. Rapid amino acid substitutions, however, can make the identification of divergent orthologs difficult using only nucleotide sequence data. Thus, more targeted approaches are required to properly identify Acps, even in species with completed genomes. In this study I propose to create four accessory gland specific cDNA libraries to identify Acps in Drosophila sechellia, D. mauritiana, D. yakuba and D. miranda, I will then annotate these genes and use the D. miranda Acps to determine those present in the full genome of its close relative D. pseudoobscura. Combining this data with the Acps already identified in D. melanogaster and D. simulans will produce a total of seven species, I will then use maximum likelihood fit evolutionary models to the divergence data to characterize the selective pressures influencing the evolution of seminal fluid proteins across these seven species. Sites identified with excess amino acid substitutions will be strong candidates for evidence of positive selection. Parameterization of these models using seven species will provide excellent power to detect evolutionary forces acting on specific lineages or on specific functional classes of genes. Finally, I will then determine the functional conservation of Acps using transgenic D. melanogaster expressing heterospecific accessory gland proteins.