Data from: Conservation of sex-linked markers among conspecific populations of a viviparous skink, Niveoscincus ocellatus, exhibiting genetic and temperature-dependent sex determination

Sex determination systems are exceptionally diverse and have undergone multiple and independent evolutionary transitions among species, particularly reptiles. However, the mechanisms underlying these transitions have not been established. Here we tested for differences in sex-linked markers in the only known reptile that is polymorphic for sex determination system, the spotted snow skink, Niveoscincus ocellatus, to quantify the genomic differences that have accompanied this transition. In a highland population, sex is determined genetically, whilst in a lowland population, offspring sex ratio is influenced by temperature. We found a similar number of sex-linked loci in each population, including shared loci, with genotypes consistent with male heterogamety (XY). However, population-specific linkage disequilibrium suggests greater differentiation of sex chromosomes in the highland population. Our results suggest that transitions between sex determination systems can be facilitated by subtle genetic differences.

性别决定系统具有极高的多样性，且在多个物种间经历了多次独立的演化转变，在爬行动物类群中这一现象尤为突出。然而，这些转变背后的分子机制尚未得到阐明。本研究以目前已知唯一存在性别决定系统多态性的爬行动物——斑点雪石龙子（Niveoscincus ocellatus）为研究对象，通过检测其不同种群间的性别连锁标记差异，量化伴随该系统转变的基因组差异。该物种的高原种群以遗传方式决定性别，而低地种群的后代性别比例受温度调控。我们在两个种群中发现了数量相近的性别连锁位点，其中包含共享位点，其基因型均符合雄异配性别（male heterogamety，XY型）系统。但种群特异性的连锁不平衡分析结果显示，高原种群的性染色体分化程度更高。本研究结果表明，性别决定系统间的转变可通过细微的遗传差异得以推动。