Evolution of a New Gene and Speciation

描述（由申请人提供）： 总的目标是通过分析一个最近重复的基因，这是参与杂种雄性不育，以了解物种分化的分子基础。 这个物种形成基因，Ods（Odysseus），在果蝇进化过程中从神经元表达基因Unc4复制而来。Unc4似乎保留了祖先的功能，而Ods则专门发挥生精作用。随着这种特化，Ods明显地迅速分化，并且这种快速分化使得当杂交种形成时，Ods在物种之间不相容（Ting等人，1998）。具体目标是回答这些问题：1. Ods序列和表达的进化：我们将比较DNA序列和表达模式，两者都在果蝇物种中迅速进化。2. Ods正常功能的进化：为了理解Ods的分化，我们将使用新的同源依赖DNA插入的方法（Rong和Golic 2000）来替换D. melanogaster与D. mauritiana和D. simulans。将测定由于替换而引起的表型和适应性变化。3. 0ds：0ds诱导的杂种不育的"异常"功能的进化被认为是"异常"功能。通过转基因实验，我们将解决的遗传机制，其中0ds不育杂交男性。

DESCRIPTION (provided by applicant): The general goal is to understand the molecular basis of species differentiation by analyzing a recently duplicated gene, which is involved in hybrid male sterility. This speciation gene, Ods (Odysseus), was duplicated from the neuron-expressing gene, Unc4, during the evolution of Drosophila. Unc4 appears to retain the ancestral functions while Ods became specialized in a spermatogenic role. With this specialization, Ods has apparently diverged rapidly and such rapid divergence has made 0ds incompatible between species when hybrids are formed (Ting et al. 1998). The specific goal is to answer these questions: 1. Evolution of Ods sequence and expression: We will compare DNA sequences and expression patterns, both evolving rapidly, across Drosophila species. 2. Evolution of the normal functions of Ods: In order to understand Ods differentiation, we will use the new method of homology-dependent DNA insertion (Rong and Golic 2000) to replace the 0ds gene in D. melanogaster with those of D. mauritiana and D. simulans. Phenotypic and fitness changes due to the replacement will be assayed. 3. Evolution of the "abnormal" function of 0ds: 0ds-induced hybrid sterility is considered the "abnormal" function. By transgenic experiments, we will address the genetic mechanism by which 0ds sterilizes hybrid males.