Data from: Dmrt1 polymorphism and sex chromosome differentiation in Rana temporaria

Sex-determination mechanisms vary both within and among populations of common frogs, opening opportunities to investigate the molecular pathways and ultimate causes shaping their evolution. We investigated the association between sex-chromosome differentiation (as assayed from microsatellites) and polymorphism at the candidate sex-determining gene Dmrt1 in two Alpine populations. Both populations harbored a diversity of X-linked and Y-linked Dmrt1 haplotypes. Some males had fixed male-specific alleles at all markers (‘differentiated’ Y chromosomes), others only at Dmrt1 (‘proto-’ Y chromosomes), while still others were genetically indistinguishable from females (undifferentiated X chromosomes). Besides these XX males, we also found rare XY females. The several Dmrt1 Y haplotypes differed in the probability of association with a differentiated Y chromosome, which we interpret as a result of differences in the masculinizing effects of alleles at the sex-determining locus. From our results, the polymorphism in sex-chromosome differentiation and its association with Dmrt1, previously inferred from Swedish populations, are not just idiosyncratic features of peripheral populations, but also characterize highly diverged populations in the central range. This implies that an apparently unstable pattern has been maintained over long evolutionary times.

普通蛙（common frogs）种群内部及种群间的性别决定机制存在变异，这为探究调控其演化的分子通路与终极成因提供了研究契机。本研究针对两个阿尔卑斯种群，分析了性染色体分化（通过微卫星标记（microsatellites）检测）与候选性别决定基因Dmrt1的多态性之间的关联。两个种群均携带多种X连锁与Y连锁的Dmrt1单倍型（haplotype）。部分雄性在所有检测标记位点均携带雄性特异性等位基因（allele），对应‘分化型Y染色体’；部分雄性仅在Dmrt1位点携带雄性特异性等位基因，对应‘原型Y染色体’；剩余雄性的遗传特征与雌性无法区分，即XX雄性。除这类XX雄性外，本研究还发现了罕见的XY雌性个体。多种Dmrt1 Y连锁单倍型与分化型Y染色体的关联概率存在差异，我们将这一现象归因于性别决定基因座（sex-determining locus）上等位基因的雄性化效应差异。研究结果显示，此前在瑞典种群中推测得出的性染色体分化多态性及其与Dmrt1的关联，并非仅为边缘种群的特有特征，同样存在于分布中心区域的高度分化种群中。这意味着这种看似不稳定的模式在漫长的演化时间尺度中得以维持。