Abstract

To clarify genetic differences between subspecies of the house mouse Mus musculus, their distribution, and hybridization, we first conducted a comparative analysis of variability of nucleotide sequences of fragments of the nuclear gene Brca1, exon 11 (2331 bp), and mitochondrial gene Cox1 (1260 bp) in 40 house mice from West and East Europe, Transcaucasia, Siberia, and Central and South Asia. Brca1 genotypes were divided into five main groups, which differed in a number of fixed substitutions. Genotypes of each group are characteristic for the certain geographical region and the following subspecies: M. m. musculus, M. m. domesticus, M. m. castaneus, and M. m. wagneri together with M. m. gansuensis; a fifth group corresponds to an unidentified subspecies or a distinct genetic form of M. musculus from India (Sikkim State). Besides the homozygous specimens, we revealed mice, which were heterozygous for all diagnostic loci simultaneously; these specimens were determined as hybrid. Hybrid mice were mainly found in the zones of contact of subspecies, but in some cases, quite far from one of the parent subspecies (possibly, due to transportation). In two hybrid mice (from Bakhtiari Province of Iran and Transbaikalia of Russia), unique Brca1 haplotypes were detected. It cannot be ruled out that, at least partly, they may be characteristic of the M. m. bactrianus and M. m. gansuensis subspecies, respectively. Thus, the results of the study showed that the nuclear Brca1 gene is a promising molecular genetic marker for the analysis of variability, differentiation, and hybridization of house mice as well for subspecific identification of M. musculus specimens. Despite more rapid evolution of the Cox1 gene, it is not well suited for discrimination of M.m. musculus, M. m. wagneri, M. m. gansuensis specimens and Transcaucasian representatives of M.m. domesticus due to introgression and long-term maintenance of foreign mitochondrial DNA in populations. However, Cox1 gene analysis (along with the diagnostics of animals by nuclear DNA) may be useful for estimation of population differences in M. m. castaneus and M.m. domesticus subspecies.

中文翻译：

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家鼠小家鼠Brca1基因，外显子11和线粒体Cox1基因片段的变异性

摘要

为了弄清楚家鼠小亚种之间的遗传差异，它们的分布和杂交，我们首先对核基因Brca1，外显子11（2331 bp）和线粒体基因Cox1（在来自西欧和东欧，Transcaucasia，西伯利亚以及中亚和南亚的40只家鼠中提取了1260 bp）。Brca1基因型被分为五个主要组，它们在许多固定取代基上有所不同。每一组的基因型是特定地理区域和以下亚种的特征。家鼠，M.米。domesticus，M.米。castaneus和。wagneri连同M.米。甘肃; 第五组对应于来自印度（锡金州）的小家鼠（M. musculus）的一个未鉴定的亚种或独特的遗传形式。除了纯合子标本外，我们还揭示了小鼠，它们同时对所有诊断基因座都是杂合的。这些标本被确定为杂种。杂种小鼠主要发现于亚种的接触区域，但在某些情况下，与亲本亚种之一相距很远（可能是由于运输）。在两只杂交小鼠（来自伊朗的巴赫蒂亚里省和俄罗斯的Transbaikalia）中，检测到独特的Brca1单倍型。不能排除它们至少部分是M.m.的特征。双峰和。甘肃亚种。因此，研究结果表明，核Brca1基因是一种有前途的分子遗传标记，可用于分析家鼠的变异性，分化和杂交以及用于鉴定小家鼠标本。尽管Cox1基因的进化更为迅速，但它并不十分适合于M. m。的鉴别。家鼠，M.米。wagneri，M.米。甘肃标本和M. m。的高加索代表。domesticus由于人口渗入和长期维护外来线粒体DNA。但是，Cox1基因分析（连同通过核DNA进行的动物诊断）可能对估计M. m。的种群差异有用。castaneus和M.米。家养亚种。