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

物种特异性基因已被证明影响生物体生育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-与古老的基因相反，即存在于多个物种中的基因-知之甚少。该项目的重点是最近起源的，串联重复的基因命名为精子特异性动力蛋白中间链（Sdic），这是以前被证明是重要的男性生育力的功能特性。该项目将帮助培训一名博士后，两名研究生，六名本科生和大量的高中生在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将公开提供给科学界。精子竞争是性选择的一个关键机制，它使交配时的生殖输出产生偏差。虽然多个基因可能会影响精子竞争，但在推动其进化方面，数量要少得多。Sdic基因是黑腹果蝇（Drosophila melanogaster）所特有的。它是另一个名为sw的基因的缺陷形式，并且存在于多个拷贝中。在同一雌性有多个父系的情况下，Sdic已经显示出影响后代数量，并且序列显示出正选择的特征。在这个项目中，Sdic对精子置换的影响将使用Sdic区域的工程版本和基于荧光的技术来分析，以跟踪女性生殖道中的精子。此外，将使用RNA-seq仔细检查多个生物样品中不同Sdic拷贝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特化的。最后，使用蛋白质组学方法，将揭示Sdic产品与sw相关的新功能特性。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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.