大林姬鼠两亚种线粒体DNA 细胞色素b 基因和控制区的序列多样性

为了研究大林姬鼠两亚种(韩国的指名亚种及中国东北和内蒙古地区的东北亚种)线粒体DNA 的变异程度并确定朝鲜亚种的分类地位,我们分别将来自韩国和中国东北长白山地区的两亚种的线粒体DNA 的细胞色素b 基因和控制区进行了测序分析。我们将测序所得到细胞色素b 基因序列与来自基因库的大林姬鼠5 个亚种的相应的单倍型进行了分析,结果显示大林姬鼠可分为4 个类群[类群1:韩国大林姬鼠指名亚种;类群2:中国长白山和内蒙古地区的东北亚种、俄罗斯外加贝尔的majuculus 亚种;类群3:中国长春的东北亚种、俄罗斯Primorye(俄罗斯远东地区) rufulus 亚种、俄罗斯库页岛(俄罗斯远东地区)和日本北海道地区的giliacus 亚种;类群4:中国黑龙江海林地区的东北亚种]。线粒体的控制区序列分析显示韩国指名亚种也不同于中国东北地区的东北亚种。本研究的类群1,2 和3 与Serizawa et al. (2002)的研究的K、S 和R 的分支相对应。这表明韩国指名亚种(类群1 和分支K)的线粒体DNA 与其他类群不同。另外,我们还发现在细胞色素b 基因构建的系统树中,东北亚种可以与类群2 (分支S)及类群3 (分支R 的不同亚种聚合在一起。我们认为线粒体DNA 的母性遗传与两个相邻亚种的个体之间的种内杂交造成了基于细胞色素b 序列对东北亚种的聚类分析结果与基于形态学特征的分类结果的不一致。因此,我们提出对这些显示出核苷酸序列多样性的东北亚种不能只用细胞色素b的数据进行亚种分类,还应该结合形态学和核DNA 特征进行进一步分析。最后,我们还发现韩国的指名亚种的细胞色素b 序列在平均距离16. 93% 的基础上不同于来自基因库的A. speciosus。Jones and Johnson (1965)指出了韩国的大林姬鼠在形态上的区别,所以我们认为韩国的大林姬鼠指名亚种A. p. peninsulae 是一种具有形态和遗传特异性的地方亚种。

Sequence diversity of the mitochondrial DNA cytochrome b gene and control region in the two subspecies of the Korean field mouse (Apodemus peninsulae)

In order to both determine the degree of mitochondrial DNA (mtDNA) divergence in the two subspecies of the Korean field mouse Apodemus peninsulae (peninsulae from Korea and praetor from northeast China and Inner Mongolia) and confirm the taxonomic status of the Korean subspecies, we sequenced the mtDNA cytochrome b gene and control region of the two subspecies of A. peninsulae from Korea and Mt. Changbai in northeast China. For the cytochrome b gene, we analyzed the sequences from this study with the corresponding haplotypes of the five subspecies of A. peninsulae from GenBank, and four groups were revealed [group 1, A. p. peninsulae from Korea; group 2, A. p. praetor from Mt. Changbai (Northeast China) and Inner Mongolia (China) and A. p. majuculus from Transbaikalia (Russia) ; group 3, A. p. praetor from Changchun (northeast China), A. p. rufulus from Primorye (Far-east Russia), and A. p. giliacus from Sakhalin (Far-east Russia) and Hokkaido (Japan) ; and group 4, A. p. praetor from Hailin (northeast China)]. In the control region, A. p. peninsulae from Korea was also different from A. p. praetor from Northeast China. First of all, the groups 1,2, and 3 of this study appeared to be coincident with the clades K, S, and R in Serizawa et al. (2002), respectively, and it was confirmed that A. p. peninsulae from Korea (group 1, clade K) is distinct in its mtDNA sequences. Moreover, we found that the specimens of A. p. praetor were grouped together with the specimens of different subspecies in groups 2 (clade S) and 3 (clade R) in this cytochrome b study. We suggest that the maternal inheritance of mtDNA and intra-specific hybridization between specimens of two adjacent subspecies in the contact zone of their subspecies border caused the incongruence between the groupings of A. p. praetor based on these cytochrome b sequences and the present classification of A. p. praetor on the basis of morphological characters. Therefore, we propose not to use the eytochrome b data alone for the designation of subspecies in A. peninsulae. Further analyses should be performed with morphometric and nuclear DNA characters from additional specimens from East Asia for the subspecies designation of A. p. praetor, which shows nucleotide sequence diversity. Finally, we also found that in the cytochrome b gene, the Korean field mouse from Korea differed from A. speciosus from GenBank with the average distance of 16.93%. Jones and Johnson (1965) noted the morphological difference of the Korean field mouse from Korea, and we concluded that the Korean field mouse from Korea, with morphological and genetic distinctiveness, is an endemic subspecies of A. p. peninsulae.