Department of Animal Science and Technology, National Taiwan University, No. 50, Ln. 155, Sec. 3, Keelung Rd., Da'an Dist., Taipei City, 106, Taiwan.
School of Life Science, National Taiwan Normal University, Taipei, 116, Taiwan.
Sci Rep. 2024 Sep 8;14(1):20898. doi: 10.1038/s41598-024-71887-1.
Taiwan harbors five endemic species of salamanders (Hynobius spp.) that inhabit distinct alpine regions, contributing to population fragmentation across isolated "sky islands". With an evolutionary history spanning multiple glacial-interglacial cycles, these species represent an exceptional paradigm for exploring biogeography and speciation. However, a lack of suitable genetic markers applicable across species has limited research efforts. Thus, developing cross-amplifying markers is imperative. Expressed sequence-tag simple-sequence repeats (EST-SSRs) that amplify across divergent lineages are ideal for species identification in instances where phenotypic differentiation is challenging. Here, we report a suite of cross-amplifying EST-SSRs from the transcriptomes of the five Hynobius species that exhibit an interspecies transferability rate of 67.67%. To identify individual markers exhibiting cross-species polymorphism and to assess interspecies genetic diversity, we assayed 140 individuals from the five species across 84 sampling sites. A set of EST-SSRs with a high interspecies polymorphic information content (PIC = 0.63) effectively classified these individuals into five distinct clusters, as supported by discriminant analysis of principal components (DAPC), STRUCTURE assignment tests, and Neighbor-joining trees. Moreover, pair-wise F values > 0.15 indicate notable between-cluster genetic divergence. Our set of 20 polymorphic EST-SSRs is suitable for assessing population structure within and among Hynobius species, as well as for long-term monitoring of their genetic composition.
台湾拥有五种特有种的蝾螈（Hynobius spp.），栖息在独特的高山地区，造成了“天空岛屿”间的族群隔离。这些物种经历了多个冰期-间冰期的演化历史，是探索生物地理学和物种形成的绝佳范例。然而，缺乏适用于各物种的合适遗传标记限制了相关研究。因此，开发跨物种扩增的标记至关重要。跨分歧演化线扩增的表达序列标签简单序列重复（EST-SSRs），对于那些表型分化具有挑战性的物种识别非常有用。在此，我们从五种 Hynobius 物种的转录组中报告了一套跨物种扩增的 EST-SSRs，其物种间的转移率为 67.67%。为了鉴定具有跨物种多态性的个体标记并评估物种间的遗传多样性，我们在 84 个采样点对来自五个物种的 140 个个体进行了分析。一组具有高物种间多态信息量（PIC = 0.63）的 EST-SSRs 有效地将这些个体分为五个不同的聚类，这得到了主成分判别分析（DAPC）、STRUCTURE 分配测试和邻接树的支持。此外，F 值的两两差异>0.15 表明了显著的聚类间遗传分化。我们这套 20 个多态性的 EST-SSRs 适合评估 Hynobius 物种内和物种间的群体结构，以及对其遗传组成的长期监测。
