CAREER: Functional and evolutionary analysis of de novo evolved genes in Drosophila male reproduction

所有物种都与其他生物体共享许多共同的基因，但每个物种都有一些最近才出现的新基因，因此要么是该物种独有的，要么只与其最亲近的亲戚共享。在多种动植物物种中，许多此类新进化的基因被认为会影响雄性生殖系统。该项目的目标是通过关注果蝇模型系统（果蝇）中影响精子功能的基因，确定新进化的基因如何影响雄性生殖成功。这项研究将产生关于新基因如何改变生殖系统以使其携带者受益的重要基础科学知识。其更广泛的影响涉及潜在制定抑制农业害虫或传播人类疾病的昆虫物种繁殖的策略，例如携带疟疾和寨卡病毒的蚊子。通过确定谱系特异性基因对雄性繁殖的重要性，这项研究可能有助于开发智能杀虫剂，或针对仅在有问题的昆虫物种中发现的基因而不是周围环境中的其他有益昆虫的基因操纵策略。该项目还将通过增加本科生对原创研究的参与和支持创新的指导项目来造福社会，这些项目鼓励来自 STEM 学科代表性不足的群体的学生坚持不懈。该研究将在一所专门的本科院校进行，部分由中级遗传学课程的学生和在教职人员实验室进行独立研究的学生进行。该项目还将支持一项计划，让来自弱势群体的一年级大学生在抵达校园后立即加入研究实验室，为这些学生提供社区意识，并在他们开始上大学时向他们介绍科学研究。最后，该项目将支持一个学生运营的组织，该组织将大学生与来自服务不足的公立高中的女孩配对，每周进行辅导课程，其中包括数学和科学技能方面的帮助。该项目特别关注最近从非编码 DNA 序列进化而来的所谓“从头”基因。先前对各种类群的研究主要集中在识别这些基因并研究它们在种群中的出现，但对其特定的分子和细胞功能知之甚少。该项目在安全且遗传上易于处理的黑腹果蝇模型系统中工作，首先将使用 RNA 干扰来筛选睾丸中表达的所有从头基因，以了解对男性生育力的影响。完全生育所需表达的基因将成为功能表征的目标，这将通过标记转基因、抗体和 CRISPR/Cas9 介导的敲除突变株系的开发而得到促进。这些工具将用于细胞学实验，以研究每个基因如何影响精子发生过程和/或成熟精子转移到雌性体内后的功能。在进行这些功能性遗传分析的同时，还将在相关果蝇物种中检查每个基因的进化历史，以了解该基因如何从非编码 DNA 序列中产生，以及它编码的蛋白质自出现以来如何进化。对于显示物种间快速分化特征的从头基因，将进行进一步的基因实验以确定分化的功能后果。总而言之，这些实验将提供新基因创造过程如何改变生殖表型的全面视图。

All species share many genes in common with other organisms, but each species has a handful of new genes that came into existence only recently and are thus either unique to that species or shared only with its closest relatives. In a variety of animal and plant species, many such newly evolved genes are thought to impact the male reproductive system. The goal of this project is to determine how newly evolved genes influence male reproductive success by focusing on those that affect sperm function in the fruit fly model system, Drosophila melanogaster. This research will generate important basic science knowledge about how new genes change reproductive systems to the benefit of their carriers. Its broader implications relate to the potential development of strategies that inhibit the reproduction of insect species that are agricultural pests or that transmit human diseases, such as the mosquitoes that carry malaria and the Zika virus. By establishing the importance of lineage-specific genes for male reproduction, this research may aid in the development of smart pesticides, or genetic manipulation strategies that target genes found only in the problematic insect species and not other beneficial insects in the surrounding environment. This project will also benefit society by increasing the participation of undergraduates in original research and supporting innovative mentoring programs that encourage the persistence of students from groups that are underrepresented in STEM disciplines. The research will be conducted at an exclusively undergraduate institution and will be carried out, in part, by students in an intermediate-level Genetics course and students conducting independent research in a faculty member's lab. The project will also support a program in which first-year college students from underrepresented groups join research labs immediately upon their arrival on campus, providing these students with a sense of community and introducing them to scientific research as they begin college. Finally, the project will support a student-run organization that pairs college students with girls from underserved public high schools for weekly mentoring sessions that include assistance with math and science skills.This project focuses specifically on so-called "de novo" genes that have recently evolved from non-coding DNA sequence. Previous research from a variety of taxa has focused on identifying these genes and studying their emergence within populations, but little is known about their specific molecular and cellular functions. Working in the safe and genetically tractable Drosophila melanogaster model system, this project will begin by using RNA interference to screen all de novo genes expressed in the testes for effects on male fertility. Genes whose expression is required for full fertility will become targets for functional characterization, which will be facilitated by the development of tagged transgenes, antibodies, and CRISPR/Cas9-mediated knockout mutant lines. These tools will be used in cytological experiments to investigate how each gene influences the process of spermatogenesis and/or the function of mature sperm after they are transferred to females. In parallel with these functional genetic analyses, the evolutionary history of each gene will be examined across related Drosophila species in order to understand how the gene arose from non-coding DNA sequence and how the protein it encodes has evolved since its emergence. For de novo genes that show signatures of rapid divergence between species, further genetic experiments will be conducted to determine the functional consequences of divergence. Taken together, these experiments will provide a comprehensive view of how the process of new gene creation can modify reproductive phenotypes.