GENETICS OF HYBRID STERILITY IN DROSOPHILA

该项目的目的是了解遗传基础， 通过分析杂种的不育性，在分子水平上进行物种形成 男性。 核心问题是是否存在主要基因， 导致果蝇种间杂种完全雄性不育 如果是这样的话，这些基因如何在分子水平上被表征， 水平 我们建议将X染色体的小片段从 D. mauritiana或D. sechellia插入D.重复的模拟 回交 渗入将首先通过一个子集来鉴定， 9个可见标记，然后通过一系列X-连锁DNA克隆。 1. Ods基因的精细定位和分子克隆 证明了杂种雄性不育的一个主要因素，Ods，存在 在16 DE中，500 kb的间隔内我们有22个交叉点 （附录1）。 我们建议将Ods划分为字母划分， 使用基于来自以下的引物序列的PCR-SSCP分析： 宇宙克隆体 10-20个以上的具有交叉点的渐渗系， 然后通过进行PCR-SSCP筛选该更精细的间隔， 两个侧翼DNA位点之一。 重叠的克隆覆盖了 整个字母间隔将被隔离。 我们的目标是定义Ods 20kb。 2-3. Ods-Light的细胞学、分子生物学及进一步遗传学分析 显微镜和二维蛋白质凝胶电泳将是 执行。 当Ods被精确定位时，转录本分析和， 最终将进行生殖系转化。 遗传 与邻近基因的相互作用，D. 将分析模拟和EMS诱导的突变。 4. Y-Rb-NP-区不育性的完全分析 从D. mauritiana和D.塞切利亚将被带到 出去 对第二个区域的分析将同样广泛， 详细的Ods基因，包括遗传，细胞学和 分子表征 5. 与由np-v-m-g标记的区域相关的不育性将是 以字母划分的分辨率通过粗略的映射来描绘。 当 所有的实验都完成了，80%的X染色体将 已经分析过了。 6. 我们将通过对Y染色体的分析， 将来自D. simulans into the two 兄弟种，而D. mauritiana转化为D. simulans （附录5、6）。 它将是对角色的最全面的分析 Y染色体在杂种雄性不育中的作用。

The objective of this project is to understand the genetic basis of speciation at the molecular level by analyzing the sterility in hybrid males. The central questions is whether there exist major genes that cause complete male sterility in the interspecific hybrids of Drosophila and, if they do, how these genes can be characterized at the molecular level. We proposed to introgress small segments of the X chromosome from D. mauritiana or D. sechellia into the genome of D. simulans by repeated backcrossing. The introgressions will be identified fist by a subset of nine visible markers and then by a series of X-linked DNA clones. 1. Fine mapping and molecular cloning of the Ods gene-We have demonstrated that a major factor for hybrid male sterility, Ods, exists in 16DE, a 500kb interval within which we have 22 crossover points (Appendix 1). We propose to demarcate Ods within a letter division by using the PCR-SSCP analysis based on the primer sequences derived from cosmic clones. 10-20 more introgression lines with a crossover point in this finer interval will then be screened by performing PCR-SSCP at either of the two flanking DNA sites. Overlapping clones covering the whole letter interval will be isolated. The goal is to define Ods within 20kb. 2-3. Cytological, molecular and further genetic analysis of Ods-Light microscopy and 2- dimensional protein gel electrophoresis will be performed. When Ods is accurately mapped, transcript analysis and, eventually, germ line transformation will be carried out. Genetic interactions with neighboring genes, polymorphic suppressor in D. simulans and EMS-induced mutations will be analyzed. 4. A complete analysis of the sterility of the y-rb-np-region introgressed from both D. mauritiana and D. sechellia will be carried out. The analyses of this second region will be as extensive and detailed as those for the Ods genes, including genetic, cytological and molecular characterizations. 5. The sterility associated with the region marked by np-v-m-g will be delineated by coarse mapping at the resolution of letter divisions. When all the proposed experiments are completed, 80% of the X chromosome will have been analyzed. 6. We will analyses the effect of Y chromosome on hybrid sterility by introgressing each of 5 Y chromosomes from D. simulans into the two sibling species and, reciprocally, from D. mauritiana into D. simulans (Appendix 5,6). It will be the most comprehensive analysis of the role of Y chromosome in the sterility of hybrid males.