Adaptive loss of an old duplicated gene during incipient speciation
Adaptive loss of an old duplicated gene during incipient speciation
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DOI：
10.1093/molbev/msj045
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发表时间：
2006-02-01
影响因子：
10.7
通讯作者：
Wu, CI
中科院分区：
文献类型：
--
作者：
Greenberg, AJ;Moran, JR;Wu, CI
为了探讨自然选择在物种起源中的作用，我们对黑腹果蝇去饱和酶2（ds 2）基因座进行了DNA多态性调查。ds 2是造成两个行为上孤立的小种-津巴布韦（Z）和大都（M）之间表皮碳氢化合物差异的原因。在Z群体中普遍存在的ds 2等位基因是功能性的，而来自M群体的等位基因在敲除其表达的基因上游具有16-bp缺失。我们在ds 2启动子中发现了正选择的信号，但在控制基因sas中没有。这种特征似乎仅限于衍生的M种群。我们还发现，选择一直是最近的，因为该基因保留了一个签名的选择性扫描证明了离开费和吴的H测试从中性的期望。我们还发现，ds 2，以及它的复制对ds 1，已保持在果蝇属至少40万年没有任何适应性变化的迹象。结合已有的分子遗传学证据，我们的结果表明，ds 2基因可能是决定D.黑腹菌
To probe the role of natural selection in species origin, we performed a DNA polymorphism survey of the Drosophila melanogaster desaturase2 (ds2) locus. ds2 is responsible for a cuticular hydrocarbon difference between two behaviorally isolated races-Zimbabwe (Z) and Cosmopolitan (M). The ds2 allele prevalent in the Z populations is functional, while the allele from the M populations harbors a 16-bp deletion Upstream of: the gene which knocks out its expression. We find a signature of positive selection ill the ds2 promoter, but not in the control gene, sas. This signature appears to be confined to the derived M population. We also find that the selection has been recent because the gene retains a signature of a selective sweep evidenced by the departure of Fay and Wu's H test from neutral expectation. We also find that ds2, as well as its duplicate pair ds1, has been maintained in the Drosophila genus for at least 40 Myr without any sign of adaptive change. Taken together with previous Molecular genetic evidence, our results Suggest that ds2 is one of the genes responsible for adaptive divergence of the Z and M races of D. melanogaster.