Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan.
Graduate School of Global Environmental Studies, Kyoto University, Kyoto, Japan.
PeerJ. 2023 Oct 24;11:e16302. doi: 10.7717/peerj.16302. eCollection 2023.
Hybridization following secondary contact may produce different outcomes depending on the extent to which genetic diversity and reproductive barriers have accumulated during isolation. The Japanese toad, , is distributed on the main islands of Japan. In the present study, we applied multiplexed inter-simple sequence repeat genotyping by sequencing to achieve the fine-scale resolution of the genetic cluster in and . We also elucidated hybridization patterns and gene flow degrees across contact zones between the clusters identified. Using SNP data, we found four genetic clusters in and and three contact zones of the cluster pairs among these four clusters. The two oldest diverged lineages, and , formed a narrow contact zone consistent with species distinctiveness. Therefore, we recommend that these two subspecies be elevated to the species level. In contrast, the less diverged pairs of two clusters in and , respectively, admixed over a hundred kilometers, suggesting that they have not yet developed strong reproductive isolation and need to be treated as conspecifics. These results will contribute to resolving taxonomic confusion in Japanese toads.
继发接触后的杂交可能会产生不同的结果，具体取决于隔离过程中遗传多样性和生殖障碍的积累程度。日本蟾蜍分布于日本主要岛屿。在本研究中，我们应用多重简单重复序列间测序的基因分型来实现日本蟾蜍和 的精细遗传聚类分辨率。我们还阐明了在聚类之间的接触区域杂交模式和基因流动程度。使用 SNP 数据，我们在日本蟾蜍和 中发现了四个遗传聚类和这四个聚类中的三个聚类对之间的三个接触区。两个最古老的分化谱系 和 形成了一个狭窄的接触区，与物种独特性一致。因此，我们建议将这两个亚种提升为独立物种。相比之下， 和 中分化程度较低的两个聚类对混合了一百多公里，表明它们尚未形成强烈的生殖隔离，需要被视为同一种群。这些结果将有助于解决日本蟾蜍分类上的混乱。
