Sex-lethal (Sxl) is the sex determination switch in Drosophila, and also plays a critical role in germ-line stem cell (GSC) daughter differentiation in Drosophila melanogaster. Three female-sterile alleles at Sxl in Drosophila melanogaster were previously shown to genetically interact to varying degrees with the maternally inherited endosymbiont Wolbachia pipientis. Given this genetic interaction and W. pipientis ability to manipulate reproduction in Drosophila, we carried out a careful study of both the population genetics (within four Drosophila species) and molecular evolutionary analysis (across 20 Drosophila species) of Sxl. Consistent with earlier studies, we find that selective constraint has played a prominent role in Sxls molecular evolution within Drosophila, but we also observe patterns that suggest both episodic bursts of protein evolution and recent positive selection at Sxl. The episodic nature of Sxls protein evolution is discussed in light of its genetic interaction with W. pipientis.

中文翻译：

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D. melanogaster物种群中性致死（Sxl）的分子种群遗传学-一个与果蝇Dolophila pipientis发生遗传相互作用的基因座

性致死（Sxl）是果蝇中的性别决定开关，并且在果蝇的种系干细胞（GSC）子代分化中也起着关键作用。先前显示果蝇果蝇Sxl的三个女性不育等位基因与母本遗传内生共生沃尔巴克氏杆菌（Wolbachia pipientis）有不同程度的遗传相互作用。鉴于这种遗传相互作用和p.pipientis操纵果蝇繁殖的能力，我们对Sxl的种群遗传学（四个果蝇物种内）和分子进化分析（横跨20个果蝇物种）进行了仔细研究。与早期研究一致，我们发现选择性限制在果蝇内Sxls分子进化中起着重要作用，但是我们也观察到了一些模式，这些模式既暗示了蛋白质进化的爆发，也表明了Sxl的近期积极选择。Sxls蛋白质进化与W.pipientis的遗传相互作用讨论了情节性质。