Dissecting the phenotypic and functional consequences of sexual selection on sperm competition through a species-specific multigene family

物种特有的基因已被证明影响生物体繁殖力和生存能力的关键方面，调节对不断变化的环境的适应。然而，这些基因是如何发挥作用的--而不是古代基因，即那些存在于多个物种中的基因--却鲜为人知。这个项目的重点是最近起源的、简单复制的名为精子特异性动力蛋白中间链(SDIC)的基因的功能特征，该基因以前被证明对男性生育能力很重要。该项目将帮助培训一名博士后、两名研究生、六名本科生和大量高中生进行基因组的功能和进化分析，特别注重纳入代表性不足的群体的成员。所有产生的数据和材料都将向科学界公开。精子竞争是性选择的一个关键机制，它在交配时会使生殖产出产生偏差。尽管多个基因可能会影响精子竞争，但推动其进化的相关基因数量要少得多。SDIC基因是黑腹果蝇特有的基因。这是另一种名为Sw的基因的缺陷形式，它以多个副本的形式存在。已经证明，在同一雌性的多个父本的情况下，SDIC会影响子代数量，并且该序列显示出正选择的特征。在这个项目中，将使用SDIC区域的工程化版本和基于荧光的技术来跟踪女性生殖道中的精子，以分析SDIC对精子移位的影响。此外，将使用RNA-SEQ仔细研究不同SDIC拷贝在多个生物样本之间的表达差异模式，这将有助于揭示至少一些SDIC拷贝是如何在功能上专门化的。最后，使用蛋白质组学方法，将发现SDIC产品与软件相关的新功能特性。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Species-specific genes have been shown to impact crucial aspects of organismal fertility and viability, mediating adaptation to changing environments. Nevertheless, how these genes exert their effects - as opposed to ancient genes, i.e. those present in multiple species - is poorly understood. This project is focused on the functional characterization of a recently originated, tandemly duplicated gene named sperm-specific dynein intermediate chain (Sdic), which was previously shown to be important for male fertility. This project will help train one postdoc, two graduate students, six undergraduates, and a large number of high-school students in functional and evolutionary analyses of genomes, with a particular focus on inclusion of members of underrepresented groups. All data and materials generated will be made publicly available to the scientific community.Sperm competition is a key mechanism of sexual selection that biases reproductive output upon mating. Although multiple genes are likely to impact sperm competition, a much lower number is relevant in driving its evolution. The Sdic gene is unique to the species Drosophila melanogaster. It is a defective form of another gene named sw, and it is present in multiple copies. Sdic has been shown to impact progeny number in cases with multiple sires of the same female, and the sequence shows signatures of positive selection. In this project, the effects of Sdic on sperm displacement will be analyzed using engineered versions of the Sdic region and fluorescence-based techniques to track the sperm in the female reproductive tract. In addition, the patterns of expression differentiation among different Sdic copies across multiple biological samples will be scrutinized using RNA-seq, which will help reveal how at least some of the Sdic copies have become functionally specialized. Lastly, using proteomic approaches, the novel functional properties of the Sdic product in relation to sw will be uncovered.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.