Cino-Japanese cooperative research on surveying genetic variants in Chinese wild mice and developing their inbred strains

在东亚，包括长江以北的大陆中国、韩国和日本，都生活着一种家鼠亚种--小家鼠，以及其他一些遗传上相近的亚种。我们称它们为肌肉亚种群。在这些区域，p-单倍型β-血红蛋白(Hbb)经常被观察到。在长江以南的中国和东南亚的菲律宾、台湾和印度尼西亚等地，栖息着卡氏小鼠亚种群，其中至少包括两种类型的卡氏小鼠。在这些地区，以d-单倍型Hbb为主。根据分子遗传分析，这两个亚种群之间的遗传差异估计约为100万年(Yonekawa等人，1981年)。最近，我们发现了一种新的Hbb单倍型W1，它分布在中国的西北部地区，频率更高(Kawashima等，1991年)。本研究对w1单倍型的b1-w1和b2-w1两个结合珠蛋白基因的cdna序列进行了分析，并与…的同源性进行了比较。Fd单倍型b1-d和b2-d较多，p-单倍型b1-p和b2-p较多。B1-d和b1-p的序列非常相似，b2-w1和b2-p的序列也很相似。另一方面，在b1-d和b1-w1之间以及b2-d和b2-w1之间也检测到了几个核苷酸替换。这些发现表明，小鼠亚种分化后，d-单倍型和w1-单倍型Hbb染色体发生重组，产生含有b1-d和b2-w1基因的p-单倍型。因此，p-单倍型可能是一个亚种间的重组。在上述项目中进行的进一步的家鼠亚种地理调查表明，在俄罗斯东部，即中国北部，存在d-单倍型的Hbb，这表明除了中国南部外，该地区还可能有卡氏亚种群的分布。可以认为有两种可能性：(1)远古时代，卡氏野鼠亚种群曾一度从东南亚蔓延到俄罗斯东部。后来，肌肉亚种群从西亚入侵到蓖麻属分布的中部地区。(2)最近从东南亚用货船向俄罗斯东部运送了卡萨内斯鼠亚种群。为了得到更可信的结论，有必要对亚洲小鼠的DNA进行精确的分析。较少

In east Asia including mainland China north of Yangtze River, Korea and Japan, a house mouse subspecies, Mus musculis musculus, and some other genetically close ones inhabit. We call them musculus subspecies group. In those regions, p-haplotyoe beta-hemoglobin (Hbb) is frequently observed. In China south of Yangtze River and southeast Asia such as the Philippines, Taiwan and Indonesia, castaneus subspecies group of mice which includes as least two types of Mus musculus castaneus inhabit. In these regions, d-haplotype Hbb is predominant. Genetic divergence between those two subspecies groups has been estimated roughly one million yeare based on molecular genetic analyzes (Yonekawa et al, 1981). Recently we have found a novel Hbb haplotype w1 which is distributed in northwestern region of China with the higher frequency (kawashima et al, 1991). In this study nucleotide siquences of cDNAs in the two hamoglobin genes, b1-w1 and b2-w1, of w1 haplotype were analyzed and compared with those o … More f d haplotype, b1-d and b2-d, and those of p-haplotype, b1-p and b2-p. The sequences of b1-d and b1-p were quite similar, and those of b2-w1 and b2-p as well. On the other hand, several nucleotide substitutions were detected between b1-d and b1-w1 and also between b2-d and b2-w1. These findings suggest a possibility that after differentiation of Mus musculus subspecies, a recombination occurred between d-haplotype and w1-haplotype Hbb chromosomes, which produced p-haplotype with b1-d and b2-w1 genes. Thus, p-haplotype coule be an inter-subspecies recombinant.Further geographical survey of house mouse subspecies carried in the oresent project demonstarated the oresence of d-haplotype of Hbb in east Russia, that is, north of northern China, which suggests possible distribution of castaneus subspecies group in that region in addition to southern China. Twopossibilities could be assumed : (1) In ancient time, castaneus subspecies group of wild mice had once spread their distribution from southeast Asia up to east Russia. Later, musculus subspecies group invaded into the central region of castaneus distribution from west Asia. (2) To east Russia, castaneus subspecies group of mice were recently transported by cargo boats from southeast Asia. Precise analysis of in Asian mouse DNAs is necessary to obtain the more plausible conclusion. Less