Nagata Nobuaki, Kubota Kohei, Sota Teiji
Department of Zoology, Graudate School of Science, Kyoto University, Kyoto, Japan.
Zoolog Sci. 2007 May;24(5):465-74. doi: 10.2108/zsj.24.465.
To study the phylogeography of the ground beetle Carabus yamato in Japan, we compared 1,020-bp sequences of the mitochondrial NADH dehydrogenase subunit 5 (ND5) gene from 373 specimens from 37 localities with those of three parapatric species (C. albrechti, C. kimurai, and C. japonicus) that might share mitochondrial lineages with C. yamato through introgressive hybridization. We found 81 haplotypes from C. yamato. Of these, 17 haplotypes were considered to be of an introgressed lineage from C. albrechti, based on the phylogeny and geographic distribution. In addition, one haplotype of C. kimurai was likely an introgressant from C. yamato. Putative introgression events among the four species were restricted to these two directional cases. We analyzed the phylogeography of C. yamato using nested clade phylogeographical analysis and population genetic parameters. The mitochondrial lineages of C. yamato were estimated to have diverged no more than approximately 1.12 million years ago, implying that the estimated historical events occurred after the Early Pleistocene. Carabus yamato was inferred to have experienced a contraction of its distribution range, followed by recent range expansion. Populations in the western and eastern regions, segregated by Ise Bay and the Nobi and Okazaki Plains, diverged in the mitochondrial clades. The northern and most western populations possessed one clade only (except an introgressed lineage), whereas eastern and some southwestern populations possessed several diverged clades, which were considered to be ancestral; these populations may have been associated with refugia during glacial periods.
为了研究日本大和步甲（Carabus yamato）的系统地理学，我们比较了来自37个地点的373个标本的线粒体烟酰胺腺嘌呤二核苷酸脱氢酶亚基5（ND5）基因的1020 bp序列，以及三种邻域分布物种（阿尔布雷希特步甲C. albrechti、木村步甲C. kimurai和日本步甲C. japonicus）的相应序列，这三种步甲可能通过渐渗杂交与大和步甲共享线粒体谱系。我们在大和步甲中发现了81个单倍型。其中，基于系统发育和地理分布，17个单倍型被认为是来自阿尔布雷希特步甲的渐渗谱系。此外，木村步甲的一个单倍型可能是来自大和步甲的渐渗种。这四个物种之间假定的渐渗事件仅限于这两个方向的情况。我们使用嵌套分支系统地理学分析和群体遗传参数分析了大和步甲的系统地理学。大和步甲的线粒体谱系估计分歧时间不超过约112万年前，这意味着估计的历史事件发生在早更新世之后。推断大和步甲经历了分布范围的收缩，随后是近期的范围扩张。被伊势湾以及浓尾平原和冈崎平原分隔的西部和东部地区的种群，在线粒体分支上出现了分歧。北部和最西部的种群仅拥有一个分支（除了一个渐渗谱系），而东部和一些西南部的种群拥有几个分歧的分支，这些分支被认为是祖先分支；这些种群可能在冰川期与避难所有关。
