A TEST OF NEUTRAL MOLECULAR EVOLUTION IN DROSOPHILA

这项拟议的研究测试了自然选择是否对 维持物种内的多态和遗传分化 在物种之间，以及如果选择是为了区分 不同种类的选择。这一分析联合依赖于一个强大的 确定多个等位基因DNA序列的新策略 基因和一组新的统计检验来区分进化 力量。通过比较物种内的核苷酸多态和差异 在物种之间，统计测试允许遗传漂移，阳性 选择(自适应变化)、否定选择(自适应约束)和 平衡选择(杂合子优势)与之相区别 又一个。这些测试还将解决氨基酸在体内的替代问题 蛋白质进化是由遗传漂移或正向选择决定的。 这项研究的目标是了解人类进化的原因 蛋白质变异的两种主要模式：非多态基因座和基因座 具有中频等位基因。核苷酸多态水平将 三种近缘果蝇各有6个基因座的测定 物种。已经选择了这些基因座，以便可以进行特定的预测 关于影响它们进化的选择模式。 天然蛋白质的遗传变异种类 人口，而作用在他们身上的选择的力量是直接的 对遗传病问题的兴趣和对变异的反应 环境条件。

The proposed research tests whether natural selection contributes to the maintenance of polymorphism within species and to genetic divergence between species, and if selection is operating to distinguish between different kinds of selection. The analysis relies jointly on a powerful new strategy for determining the DNA sequences of many alleles of the same gene and on a new set of statistical tests for distinguishing evolutionary forces. By comparing nucleotide polymorphism within species to divergence between species the statistical tests allow genetic drift, positive selection (adaptive change), negative selection (adaptive constraint) and balancing selection (heterozygote advantage) to be distinguished one from another. The tests will also address whether amino acid substitutions in protein evolution are governed by genetic drift or by positive selection. The goal of the study is to understand the evolutionary cause of two major patterns of protein variation: loci with no polymorphism and loci with Intermediate frequency alleles. Nucleotide polymorphism levels will be determined for six gene loci in each of three related Drosophila species. The loci have been chosen so that specific predictions can be made about the mode of selection affecting their evolution. The kinds of genetic variation in proteins in natural populations, and the forces of selection operating on them is of direct interest to problems of genetic disease and to variation In response to conditions of the environment.