Trans-species variation in Dmrt1 is associated with sex determination in four European tree-frog species
Trans-species variation in Dmrt1 is associated with sex determination in four European tree-frog species
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DOI：
10.1111/evo.12891
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发表时间：
2016-04-01
期刊：
影响因子：
3.3
通讯作者：
Perrin, Nicolas
中科院分区：
文献类型：
--
作者：
Brelsford, Alan;Dufresnes, Christophe;Perrin, Nicolas
对偶尔XY重组与性染色体周转在防止性染色体分化中的相对作用的实证研究可能揭示作用于性别决定系统的进化力量。XY重组的标记难以与同源转换的标记区分开（即，保持性别染色体身份的性别决定系统中的转换）：两种模型都预测性连锁基因中的X和Y等位基因按物种聚类。然而，XY重组模型具体预测的反向模式（配子体聚类）的那些基因直接参与性别决定。因此，后一种模型只能通过鉴定与性别相关的跨物种多态性的祖先性别决定区（SDR）来验证。在这里，我们结合联合收割机的候选基因的方法与基因组扫描，以确定一个小SDR共享的四个物种的一个单系分支的欧洲树蛙。该SDR至少包括Dmrt 1的N-末端部分和紧邻上游序列。我们的研究结果提供了明确的证据表明，在这个分支的结果只有XY重组的性染色体的同型性，并采取了重要的一步，对性别决定基因座的鉴定。此外，我们确定的性别诊断标记将使研究环境性别逆转在更广泛的青蛙物种。
Empirical studies on the relative roles of occasional XY recombination versus sex-chromosome turnover in preventing sex-chromosome differentiation may shed light on the evolutionary forces acting on sex-determination systems. Signatures of XY recombination are difficult to distinguish from those of homologous transitions (i.e., transitions in sex-determination systems that keep sex-chromosome identity): both models predict X and Y alleles at sex-linked genes to cluster by species. However, the XY-recombination model specifically predicts the reverse pattern (clustering by gametologs) for those genes that are directly involved in sex determination. Hence, the latter model can only be validated by identification of an ancestral sex-determining region (SDR) with trans-species polymorphism associated to sex. Here we combine a candidate-gene approach with a genome scan to identify a small SDR shared by four species of a monophyletic clade of European tree frogs. This SDR encompasses at least the N-terminal part of Dmrt1 and immediate upstream sequences. Our findings provide definitive evidence that sex-chromosome homomorphy in this clade results only from XY recombination, and take an important step toward the identification of the sex-determining locus. Moreover, the sex-diagnostic markers we identify will enable research on environmental sex reversal in a wider range of frog species.