The Role of Prezygotic and Postzygotic, Extragenomic Isolating Mechanisms in Drosophila Population Biology

合子前和合子后、基因组外分离机制在果蝇种群生物学中的作用

• 批准号: 9806649
• 负责人: Scott Pitnick
• 金额: $ 20.5万
• 依托单位: Syracuse University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9806649&HistoricalAwards=false
• 关键词: Role; Prezygotic; Postzygotic; Extragenomic; Isolating

Pitnick 9806649 Among fruitfly species, the length of sperm and of the female's sperm-storage organs have evolved very rapidly, with some species producing relatively few, gigantic sperm, as much as 20 times their body length. Such unusual sex cells challenge our understanding of the fundamental nature of sex differences and of the evolution of reproductive strategy. Two goals of the proposed work are to determine (1) the evolutionary relationship between these male and female traits and (2) the functional significance of variation in sperm and female sperm-storage organ length. To this end, populations of Drosophila melanogaster will be artificially selected for longer and shorter sperm-storage organs. Comparison between males within the selection lines and in "associated male" lines will permit discrimination of the roles of pleiotropy and sexual selection in generating a correlated response in sperm length to female sperm-storage organ length evolution. Productivity and sperm competition experiments will quantify the relationships between sperm length, female reproductive tract morphology, and patterns of sperm use by females. A third goal of the proposed work is to determine the extent to which divergence in sperm length and female reproductive tract morphology contributes to reproductive failure among populations/species. Factors that prevent interbreeding among populations, or "reproductive isolating mechanisms," are critical to the speciation process. Reciprocal crosses among the selected lines will determine the extent to which divergence in sperm and female reproductive morphology can lead to reproductive isolation among populations. Experiments determining the fate of sperm in hybrid matings among five closely related species will extend this analysis of reproductive isolating mechanisms. Number of sperm transferred, eggs fertilized, and eggs hatching per mating will be determined and used to quantify levels of sperm/female and sperm/egg compatibility for all possible hybrid a nd control crosses. Results from these studies will enhance our presently limited understanding of postmating, prezygotic and postzygotic, extragenomic reproductive isolating mechanisms and broaden our perspective on Drosophila speciation.

Pitnick 9806649 在果蝇物种中，精子和雌性精子储存器官的长度进化得非常快，有些物种产生的精子相对较少，但体积巨大，可达其身体长度的 20 倍。 这种不寻常的性细胞挑战了我们对性别差异的基本性质和生殖策略进化的理解。拟议工作的两个目标是确定（1）这些男性和女性特征之间的进化关系，以及（2）精子和女性精子储存器官长度变化的功能意义。为此，将人工选择黑腹果蝇种群的较长和较短的精子储存器官。选择品系内的雄性和“相关雄性”品系中的雄性之间的比较将允许区分多效性和性选择在产生精子长度对雌性精子储存器官长度进化的相关反应中的作用。 生产力和精子竞争实验将量化精子长度、女性生殖道形态和女性精子使用模式之间的关系。 拟议工作的第三个目标是确定精子长度和女性生殖道形态的差异在多大程度上导致种群/物种的生殖失败。阻止种群间杂交的因素或“生殖隔离机制”对于物种形成过程至关重要。 所选品系之间的相互杂交将决定精子和雌性生殖形态的差异在多大程度上会导致群体之间的生殖隔离。确定五个密切相关物种之间杂交交配中精子命运的实验将扩展对生殖隔离机制的分析。 每次交配的精子转移数量、受精卵数和孵化卵数将被确定并用于量化所有可能的杂交和对照杂交的精子/雌性和精子/卵子兼容性水平。这些研究的结果将增强我们目前对交配后、合子前和合子后、基因组外生殖隔离机制的有限理解，并拓宽我们对果蝇物种形成的看法。