Yi Soojin, Charlesworth Brian
Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637-1573, USA.
Genet Res. 2003 Oct;82(2):101-6. doi: 10.1017/s0016672303006402.
We have investigated the pattern of DNA sequence variation at the exuperantia2 locus in Drosophila pseudoobscura. This adds to the increasing dataset of genetic variation in D. pseudoobscura, a useful model species for evolutionary genetic studies. The level of silent site nucleotide diversity and the divergence from an outgroup Drosophila miranda are comparable with those for other X-linked loci. One peculiar pattern at the exu2 locus of D. pseudoobscura is a complete linkage disequilibrium between two SNPs, one of which is a replacement site. As a result, there are two distinct haplotype groups in our dataset. Based upon the comparisons with the outgroup sequences from D. miranda and Drosophila persimilis, we show that the newly derived haplotype group has lower diversity than the ancestral haplotype group. The pattern of protein evolution at exu2 shows some deviation from the neutral model. Together, these and other characteristics of the exu2 locus suggest the action of selection on the pattern of SNP variation, consistent with a partial selective sweep associated with the newly derived haplotype.
我们研究了果蝇拟暗果蝇中exuperantia2位点的DNA序列变异模式。这增加了果蝇拟暗果蝇遗传变异的数据集，果蝇拟暗果蝇是进化遗传学研究的一个有用模型物种。沉默位点核苷酸多样性水平以及与外群果蝇米兰达的分歧与其他X连锁位点的情况相当。果蝇拟暗果蝇exu2位点的一个独特模式是两个单核苷酸多态性（SNP）之间完全连锁不平衡，其中一个是替换位点。因此，我们的数据集中有两个不同的单倍型组。通过与果蝇米兰达和果蝇佩氏果蝇的外群序列进行比较，我们发现新衍生的单倍型组的多样性低于祖先单倍型组。exu2位点的蛋白质进化模式显示出与中性模型的一些偏差。总之，exu2位点的这些和其他特征表明选择作用于SNP变异模式，这与与新衍生单倍型相关的部分选择性清除一致。
