Glinka Sascha, De Lorenzo David, Stephan Wolfgang
Section of Evolutionary Biology, Department of Biology II, Ludwig-Maximilians University, Planegg-Martinsried, Germany.
Mol Biol Evol. 2006 Oct;23(10):1869-78. doi: 10.1093/molbev/msl069. Epub 2006 Jul 25.
Since Drosophila melanogaster colonized Europe from tropical Africa 10 to 15 thousand years ago, it is expected that adaptation has played a major role in this species in recent times. A previously conducted multilocus scan of noncoding DNA sequences on the X chromosome in an ancestral and a derived population of D. melanogaster revealed that some loci have been affected by directional selection in the European population. We investigated if the pattern of DNA sequence polymorphism in a region surrounding one of these loci can be explained by a hitchhiking event. We found strong evidence that the studied region around the gene unc-119 was shaped by a recent selective sweep, including a valley of reduced heterozygosity of 83.4 kb, a skew in the frequency spectrum, and significant linkage disequilibrium on one side of the valley. This region, however, was interrupted by gene conversion events leading to a strong haplotype structure in the center of the valley of reduced variation.
自从黑腹果蝇在1万到1.5万年前从热带非洲殖民到欧洲以来，预计适应在该物种近代发展过程中发挥了重要作用。先前在黑腹果蝇的一个祖先群体和一个衍生群体中对X染色体上的非编码DNA序列进行的多位点扫描显示，一些基因座在欧洲群体中受到了定向选择的影响。我们研究了这些基因座之一周围区域的DNA序列多态性模式是否可以由搭便车事件来解释。我们发现有力证据表明，围绕unc-119基因的研究区域是由近期的选择性清除塑造的，包括一个83.4 kb的杂合性降低的低谷、频谱偏斜以及低谷一侧显著的连锁不平衡。然而，该区域被基因转换事件打断，导致变异减少低谷中心出现强烈的单倍型结构。
