POPULATION GENETICS OF D SIMULANS AND D MELANOGASTER

遗传变异存在于几乎所有的自然种群中 动物，包括人类。研究作用于人类的进化过程 这种变异是基础遗传学研究的一个重要方面。这个 拟议的工作将解决两个问题。首先，什么是进化 杂合性与重组相关性的解释 在果蝇基因组中(Begin和Aquandro 1992,1993)？第二，如何 重组率、性别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在 自然人口，我们才刚刚开始了解这些力量 导致了这些模式。我们对基因的不同模式的看法 X染色体和常染色体在种内和种间的变异， 以及连锁和选择在决定沉默变异中的作用 而这些物种中的蛋白质变异实际上是基于来自 一些基因。我们对物种内蛋白质变化的知识模式是 尤其是穷人。除了少数几个基因外， 群体遗传学仍来自淀粉凝胶电泳法。 从这类数据中得出的结论令人怀疑。进化的力量 推动物种间蛋白质进化的研究也同样鲜为人知。 我建议收集的数据是专门针对填补这些 差距。它们将以小种群的DNA序列的形式出现 拟果蝇及其近亲黑腹果蝇的样本。我 建议测量沉默杂合度和氨基酸杂合度 大约100个不同的基因位于确定的染色体区域。 这些数据可能会极大地加深我们对 在几个层面上的群体遗传学。他们将为我们的 试图确定有害突变是否是一个重要因素 在塑造整个基因组的变异模式方面。他们会 有助于我们了解它们的异同 在X染色体和常染色体上的进化过程之间。 最后，这些数据将有助于我们尝试理解 作用于氨基酸的不同进化过程与沉默变异 在两个密切相关的物种中。

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.