POPULATION GENETICS OF D SIMULANS AND D MELANOGASTER

遗传变异存在于自然种群中， 动物，包括人类。研究作用于 这种变异是基础遗传学研究的一个重要方面。的 拟议的工作将处理两个问题。首先，什么是进化论？ 杂合性和重组之间相关性的解释 在果蝇基因组中（Begun and Aquandro 1992，1993）？第二，如何 重组率、性连锁和染色体位置影响蛋白质 物种内部和物种之间的进化 尽管最近成功地发现了变异是如何分布在 自然种群，我们才刚刚开始了解 导致了这些模式。我们对不同的遗传模式的看法 种内和种间X染色体和常染色体的变异， 以及连锁和选择在决定沉默变异中的作用 这些物种中的蛋白质变异是基于 一些基因。我们对物种内蛋白质变异的认识模式 尤其是穷人。除了少数基因外， 群体遗传学仍来自淀粉凝胶电泳。 从这些数据中得出的结论是可疑的。进化的力量 在物种之间驱动蛋白质进化的机制也同样模糊。 我建议收集的数据是专门针对填补这些 差距。它们将以小种群DNA序列的形式出现 果蝇和它的近亲黑腹果蝇的样本。我 建议测量沉默杂合性和氨基酸杂合性， 大约100个不同的基因位于确定的染色体区域。 这些数据可能会大大改善我们对 在几个层次上的群体遗传学。他们将为我们的 试图确定有害突变体是否是一个重要因素 在整个基因组中形成变异模式。他们将 有助于我们理解 X染色体和常染色体的进化过程之间的联系。 最后，这些数据将有助于我们了解 不同的进化过程作用于氨基酸和沉默变异 两个密切相关的物种。

Genetic variation is present in natural populations of essentially all animals, including humans. Studying the evolutionary processes acting on this variation is an important aspect of basic genetics research. The proposed work will address two issues. First, what is the evolutionary explanation for the correlation between heterozygosity and recombination in the Drosophila genome (Begun and Aquandro 1992, 1993)? Second, how does recombination rate, sex linkage, and chromosomal location affect protein evolution within and between species? Despite recent success in discovering how variation is distributed in natural populations, we are only just beginning to understand the forces that cause these patterns. Our view of the different patterns of genetic variation on the X-chromosome and autosomes within and between species, and of the role of linkage and selection in determining silent variation and protein variation in these species is really based on data from only a few genes. Our knowledge patterns of protein variation within species is especially poor. With the exception of a few genes, the primary data for population genetics are still from starch gel electrophoresis. Generalizations from such data are dubious. The evolutionary forces driving protein evolution between species are similarly obscure. The data I propose to collect are specifically aimed toward filling these gaps. They will take the form of DNA sequences from small population samples of Drosophila simulans and its close relative, melanogaster. I propose to measure silent heterozygosity and amino acid heterozygosity at approximately 100 different genes located in defined chromosomal regions. The data are likely to significantly refine our understanding of population genetics at several levels. They will contribute to our attempts to determine whether deleterious mutants are a significant factor in shaping patterns of variation across the entire genome. They will contribute to our understanding of the similarities and differences between evolutionary processes on the X chromosome and the autosomes. Finally, the data will contribute to our attempts to understand the different evolutionary processes acting on amino acid and silent variation in two closely related species.