Comparative Genomics of Seminal Fluid Proteins

副腺蛋白（Acps）是精液的重要组成部分，影响着女性的生理机能，影响着男性的健康。许多Acps似乎处于积极选择之下，可能受到性别冲突的驱动，因此是研究共同进化过程的理想候选者。然而，快速的氨基酸替换使得仅使用核苷酸序列数据难以识别不同的同源物。因此，需要更有针对性的方法来正确识别Acps，即使在具有完整基因组的物种中也是如此。在这项研究中，我建议创建四个副腺特异性cDNA文库来鉴定果蝇、毛里求斯、雅库巴和米兰达的Acps，然后我将对这些基因进行注释，并使用米兰达Acps来确定其近亲伪蛙的全基因组中存在的Acps。将这些数据与已经在D. melanogaster和D. simulans中发现的Acps结合起来，将产生总共7个物种，然后我将使用最大似然拟合进化模型来分析差异数据，以表征影响这7个物种精液蛋白进化的选择压力。具有过量氨基酸取代的位点将成为积极选择的有力证据。使用七个物种的这些模型的参数化将为检测作用于特定谱系或特定功能类别的基因的进化力提供出色的能力。最后，我将使用表达异源附属腺蛋白的转基因d.m anogaster来确定Acps的功能保护。

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.