Aoki Gen, Matsui Masafumi, Nishikawa Kanto
Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho Sakyo-ku, Kyoto 606-8501, Japan.
Zoolog Sci. 2013 Mar;30(3):167-73. doi: 10.2108/zsj.30.167.
The Tohoku salamander, Hynobius lichenatus Boulenger, 1883, is a lentic breeding species widespread throughout montane regions of northeastern Japan. To explore intraspecific genetic variation and infer evolutionary history of H. lichenatus, we performed mitochondrial DNA analysis (complete 1141 bp sequences of the mitochondrial cytochrome b gene) using 215 adult and larval individuals collected from 75 localities, encompassing known distributional range of the species. Hynobius lichenatus proved to be monophyletic, including three well-supported and geographically structured clades (Clade I from northern Kanto, Clade II from southern Tohoku, and Clade III from northern Tohoku). These clades, respectively, comprise several subclades, and show genetic distances as large as those seen between different species of Hynobius. Results of population statistic analyses indicate that all clades and most subclades have maintained high genetic diversity and demographic stability over long periods. Molecular dating indicates divergence in H. lichenatus concords with topographic evolution of northeastern Japan from late Miocene to early Pleistocene, suggesting that paleogeographic events in this region, such as orogenesis, sea level change, and volcanic activity, have been crucial for shaping genetic patterns and diversity in this species. Hynobius lichenatus greatly differs from many other animal species from northeastern Japan in its much older periods and the pattern of genetic differentiation, and is suggested as an old faunal element in this region.
东北蝾螈（Hynobius lichenatus Boulenger，1883年）是一种在日本东北部山区广泛分布的静水繁殖物种。为了探索东北蝾螈的种内遗传变异并推断其进化历史，我们使用从75个地点采集的215只成年和幼年个体进行了线粒体DNA分析（线粒体细胞色素b基因的完整1141 bp序列），这些地点涵盖了该物种已知的分布范围。结果表明，东北蝾螈是单系的，包括三个得到充分支持且具有地理结构的分支（分支I来自关东北部，分支II来自东北南部，分支III来自东北北部）。这些分支分别包含几个亚分支，并且显示出与不同种类的 hynobius 之间一样大的遗传距离。种群统计分析结果表明，所有分支和大多数亚分支在很长一段时间内都保持了高遗传多样性和种群稳定性。分子年代测定表明，东北蝾螈的分化与日本东北部从中新世晚期到更新世早期的地形演化一致，这表明该地区的古地理事件，如造山运动、海平面变化和火山活动，对塑造该物种的遗传模式和多样性至关重要。东北蝾螈在其古老的时期和遗传分化模式上与日本东北部的许多其他动物物种有很大不同，被认为是该地区古老的动物区系成分。
