DISSERTATION RESEARCH: The Genomics of Hybrid Sterility & Speciation in the Anopheles gambiae Species Complex

该项目将调查一组已知传播疾病的蚊子中驱动物种形成的遗传机制。在这组蚊子中，不同物种的数量传统上被低估了，因为虽然外观上无法区分，但该组实际上由多个遗传上不同的物种组成。尽管它们对人类很重要，但人们对这些物种是如何产生的知之甚少。该项目解决了蚊子遗传学中的三个问题。首先，哪些基因是造成物种间生殖隔离的原因？第二，这些基因是如何随着时间的推移而分化，从而导致物种形成的？第三，两个物种之间的变化模式在不同的物种对之间是否一致？这些物种中有几种是撒哈拉以南非洲人类疟疾的主要媒介。除了帮助我们了解创造生物多样性的遗传过程外，该项目还具有额外的社会效益，因为它可以通过识别导致蚊子不育的基因来帮助开发和实施新的遗传病媒控制措施。冈比亚按蚊的名称实际上与八种遗传上不同但最近分化的物种的物种复合体有关，这些物种无法根据形态学进行识别。该复合体是物种形成遗传学研究的一个重要系统，因为复合体中的物种表现出广泛的遗传分化，包括部分孤立的亚种。因此，这种物种复合体使这些研究人员能够研究物种形成。当复合体的不同物种杂交时，雄性后代是不育的，而雌性后代是可育的。如果一个杂交的雌性与任何一个亲本物种的雄性交配，所产生的第二代杂交种由于遗传不相容而表现出不同程度的不育性。这允许通过对许多回交后代进行测序来对不育原因进行基因组作图。这项研究将因此地图的基因组区域，导致雄性和雌性不育的回交杂交两个物种之间（一个。gambiae和An. quadriannulatus）。本文结合现有的安氏按蚊回交后代的雄性不育性和雌性不育性研究资料，对安氏按蚊回交后代的雄性不育性进行了研究。gambiae和An.该数据将确定相同的基因组区域是否导致不同物种对的不育性。通过比较多个物种对的分歧模式及其原因，该研究将增加我们对一个重要动物群体中驱动物种形成的因素的理解。

This project will investigate genetic mechanisms driving speciation in a group of mosquitos known to transmit disease. In this group of mosquitos the number of different species has traditionally been underestimated because, while indistinguishable in appearance, the group is actually comprised of multiple genetically distinct species. Despite their importance to humans little is known about how these species arose. This project addresses three questions in mosquito genetics. First what genes are responsible for reproductive isolation between the species? Second, how do those genes diverge across time leading to speciation? And third is the pattern of change between two species consistent across different pairs of species? Several of these species are the major vectors of human malaria in sub-Saharan Africa. In addition to helping us understand the genetic process that creates biological diversity, this project therefore has additional societal benefits as it may help in the development and implementation of novel genetic vector control measures by, identifying genes causing sterility in mosquitoes.The name Anopheles gambiae is actually associated with a species complex of eight genetically distinct but recently diverged species that cannot be identified based on morphology. The complex is an important study system for the field of speciation genetics because species in the complex exhibit a wide range of genetic divergence, including partially isolated sub-species. Therefore this species complex allows these researchers to study speciation as it unfolds. When different species of the complex hybridize, the male offspring are sterile and females are fertile. If a hybrid female mates with a male of either parental species, the resulting second-generation hybrids exhibit varying levels of sterility due to genetic incompatibility. This allows genomic mapping of the causes of sterility through sequencing of many backcross offspring. This study will thereby map regions of the genome that cause male and female sterility in backcross hybrids between two species (An. gambiae and An. quadriannulatus). Combined with existing data on male and female sterility in backcross hybrids between An. gambiae and An. arabiensis this data will determine if the same genomic regions cause sterility across different species pairs. By comparing the patterns of divergence and their causes across multiple species pairs the research will increase our understanding of the factors driving speciation in an important group of animals.