RUI Collaborative Research: Genetic and Developmental Analysis of Hybrid Sterility Rescue between Drosophila Melanogaster and Drosophila Simulans

Hollocher/Davis 9728890当不同物种杂交在一起时，一个引人注目的和非常常见的模式是产生不能繁殖的杂交后代（即后代完全不育）。 本研究的重点是了解黑腹果蝇和拟果蝇杂交后代杂种不育的遗传和发育基础。早期对杂种不育性的分析受到了阻碍，因为使用这两个物种的所有杂交都会产生完全不育的后代，这使得不可能进行超出最初F1杂种的简单遗传分析。最近，一个自然发生的D. simulans在与D.黑腹菌有能力产生可育和不育的杂交雌性，我们现在能够使用这些果蝇物种中可用的大量分子和遗传工具，以了解杂交不育的潜在遗传和发育原因。本研究的第一个目的是使用比较发育的方法来描述与杂种不育相关的配子发生的特定缺陷。利用这种比较方法，我们可以回答以下问题：雌性杂种不育及其挽救的发育基础是什么？不育的、未被拯救的杂交雌性是否有任何功能性的生殖细胞组织？如果是这样，生殖细胞发育的主要缺陷是什么？杂交雌性不育拯救完成了吗？杂种不育拯救是性别特异的吗？我们的第二个目标是绘制遗传因素负责杂交雌性不育和拯救。D. simulans品系，当与D.将使用melanogaster来确定哪些基因区域与本发明的第一个目的中表征的特定杂种不育缺陷相关。在定位研究的同时，将对其他果蝇品系进行调查，以分离新的不育拯救因子，特别注意果蝇的互补品系。显示杂种不育拯救。我们的最终目标是利用杂交不育拯救D。melanogaster和D. simulans将一个物种的遗传物质引入另一个物种，以测试关于影响配子发生的基因如何在这两个物种之间分化的特定假设。

Hollocher/Davis 9728890 One striking and very common pattern that results when different species are crossed together is the production of hybrid offspring that are unable to reproduce (i.e. the offspring are completely sterile). This research focuses on understanding the genetic and developmental basis of hybrid sterility in offspring that result from crosses between Drosophila melanogaster and Drosophila simulans. Earlier analyses of hybrid sterility had been hampered by the fact that all crosses using these two species yielded offspring that were completely sterile, making simple genetic analyses beyond the initial F1 hybrid impossible. Recently, a naturally occurring strain of D. simulans has been discovered which rescues the sterility defect of hybrid females in crosses with D. melanogaster. With the ability to produce both fertile and sterile hybrid females, we are now in a position to use the vast repertoire of molecular and genetic tools available in these Drosophila species to make advances in understanding the underlying genetic and developmental causes of hybrid sterility. The first aim of this research is to use a comparative developmental approach to characterize the specific defects in gametogenesis that are associated with hybrid sterility. Using this comparative approach we can answer the following questions: What is the developmental basis of female hybrid sterility and its rescue? Do sterile, unrescued hybrid females have any functional germline tissue at all? If so, what appears to be the primary defect in germline development? Is hybrid female sterility rescue complete? Is hybrid sterility rescue sex-specific? Our second aim is to map the genetic factors responsible for hybrid female sterility and its rescue. The generation of recombinants between D. simulans lines that produce either sterile or fertile hybrid females when crossed with D. melanogaster will be used to determine which gene regions are associated with the specific hybrid sterility defects characterized in t he first aim of the proposal. In conjunction with the mapping studies, a survey of additional Drosophila lines will be conducted to isolate new sterility rescue factors, paying particular attention to complementary strains of D. melanogaster which show hybrid sterility rescue. Our final aim is then to take advantage of hybrid sterility rescue in crosses between D. melanogaster and D. simulans to introduce genetic material from one species into the other to test specific hypotheses about how genes affecting gametogenesis have diverged between these two species.