Genetic and functional analyses of sperm length evolution in Drosophila

精子是最多样化的细胞类型，表现出快速和戏剧性的进化变化。 然而，精子形态的遗传学和适应性意义却知之甚少。 本研究的目的是：（1）研究精子长度与雌性生殖道内的活动性/行为之间的关系，（2）鉴定对精子长度有重要影响的基因。 这些研究将在果蝇（Drosophila melanogaster）种群中进行，这些果蝇在实验中进化为具有异常短或长的精子，以及几个在精子长度上有很大差异的密切相关物种。所有的种群都经过基因工程改造，使精子的头部在荧光灯下发出绿色或红色的光。 这种材料将使，在第一次调查中，明确的歧视精子从不同的男性在两次交配的女性，以及直接观察在体内的实时精子活力和精子-精子和精子-女性的相互作用。 第二项调查将使用突破性的基因测序技术（即，限制位点相关DNA图谱），以确定与精子长度变异相关的基因。拟议的研究有可能在生殖生理学和遗传学，性选择和物种形成领域产生分水岭的进展。 许多本科生和研究生将在这项工作的过程中接受培训。由此产生的进展，我们的理解在女性的精子行为和候选基因的识别有助于精子的形式也可能导致我们的理解和治疗人类不育症的进步，并在进一步发展用于保护受威胁和濒危物种的辅助生殖技术。

Spermatozoa are the most diverse cell type, exhibiting rapid and dramatic evolutionary changes in form. However, the genetics and adaptive significance of sperm form are poorly understood. Investigations are proposed (1) to examine the relationship between sperm length and motility/behavior within the female reproductive tract, and (2) to identify genes of major influence on sperm length. These studies will be conducted with populations of the fruit fly Drosophila melanogaster that have been experimentally evolved to have unusually short or long sperm, and several closely related species differing substantially in sperm length. All populations have been genetically engineered to produce sperm whose heads glow green or red under fluorescent light. This material will enable, in the first investigation, unambiguous discrimination among sperm from different males within twice-mated females, as well as direct observation in vivo of real-time sperm motility and sperm-sperm and sperm-female interactions. The second investigation will use breakthrough gene sequencing technology (i.e., restriction-site associated DNA mapping) to identify genes associated with sperm length variation.The proposed research has the potential to generate watershed advances in the fields of reproductive physiology and genetics, sexual selection and speciation. Many undergraduate and graduate students will be trained in the course of this work. Resulting progress in our understanding of sperm behavior within females and the identification of candidate genes contributing to sperm form are also likely to lead to advances in our understanding and treatment of human infertility and in the further development of assisted reproductive technologies used in the preservation of threatened and endangered species.