The recent demographic and adaptive history of Drosophila melanogaster⋆
The recent demographic and adaptive history of Drosophila melanogaster⋆
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DOI：
10.1038/sj.hdy.6800901
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发表时间：
2007-02
期刊：
影响因子：
3.8
通讯作者：
W. Stephan;Haipeng Li
中科院分区：
文献类型：
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作者：
W. Stephan;Haipeng Li
过去20年的群体遗传分析证实了L Tsacas和D Lachaise的早期假设，即世界性物种黑腹果蝇起源于非洲热带，并且直到最近才殖民于世界其他地区。基于多位点数据的最大似然分析表明，假定的祖先非洲人口在大约6万年前扩大了规模。这些人口变化伴随着许多有益突变的固定，正如基因组中正向选择的特征（选择性扫描）所揭示的那样。X染色体上的适应性取代率估计为每代每个核苷酸位点10 - 11。在非洲以外的新栖息地殖民的衍生种群中发现了类似的（但不是显著更高的）替代率，例如从非洲血统中分支出约16000 ya的欧洲种群。
Population genetic analyses of the past two decades confirmed an earlier hypothesis by L Tsacas and D Lachaise that the cosmopolitan species Drosophila melanogaster has an Afrotropical origin, and that it colonized the rest of the world only very recently. Maximum likelihood analyses based on multilocus data suggest that the putative ancestral African population expanded its size about 60 000 years ago (ya). These demographic changes were accompanied by the fixation of numerous beneficial mutations, as revealed by signatures of positive directional selection in the genome (selective sweeps). The estimated rate of adaptive substitution on the X chromosome is in the order of 10− 11 per nucleotide site per generation. Comparable (but not significantly higher) substitution rates are found in derived populations that colonized new habitats outside Africa, such as in a European population that branched off from the African lineage about 16 000 ya.