The genetic status of two insular populations of the endemic spiny rat Tokudaia osimensis (Rodentia, Muridae) of the Ryukyu Islands, Japan
The genetic status of two insular populations of the endemic spiny rat Tokudaia osimensis (Rodentia, Muridae) of the Ryukyu Islands, Japan
复制标题
日本琉球群岛特有刺鼠 Tokudaia osimensis（啮齿目，鼠科）两个岛屿种群的遗传状况
DOI：
10.3106/mammalstudy.24.43
复制
发表时间：
1999
期刊：
影响因子：
1
通讯作者：
K. Tsuchiya
中科院分区：
文献类型：
--
作者：
Hitoshi Suzuki;M. Iwasa;N. Ishii;H. Nagaoka;K. Tsuchiya
本研究以琉球群岛德野岛和奄美大岛为研究对象，通过细胞色素B（cyt B）α 1基因的序列分析和核糖体RNA基因（rDNA）的限制性片段长度多态性（RFLP）分析，研究了该种的地理变异。这两个群体显示出内在的核型变异（Tokuno-shima，2n=45; Amami-oshima，2n=25）。cyt B基因的序列在两个岛屿种群之间差异很大。使用Kimura双参数方法计算出该基因的1，140 bp之间的序列差异程度为0.088，并且与啮齿类动物的相关物种之间的差异程度相当，例如小鼠属或鼠属。rDNA-RFLP的分化程度也很高。三个22限制性位点的变异被发现固定在核rDNA阵列的数百个副本中的两个岛屿人口之一。这些密集的种群间的差异表明，这两个岛屿的人口可能已经被隔离了相当长的一段时间的进化时间，可能是几百万年，尽管有几个机会，更新的遗传接触在更新世冰期。我们的数据强烈表明，目前的分类地位的人口的两个岛屿，奄美大岛和德野岛，这把他们同种，应加以审查。
We examined the geographic variation of Tokudaia osimensis through the analysis of mitochondria1 cytochrome b (cyt b) gene sequences and the restriction fragment length polymorphism (RFLP) in the nuclear ribosomal RNA gene (rDNA), using samples collected from Tokuno-shima and Amami-oshima in the Ryukyu Islands. The two populations show intrinsic karyological variation (Tokuno-shima, 2n=45; Amami-oshima, 2n=25). Sequences of the cyt b gene differed considerably between the two island populations. The extent of the sequence divergence among 1,140 bp of the gene was calculated to be 0.088 using the Kimura two parameter method, and was comparable to those between related species of rodents such as within genus Mus or Rattus. The extent of the differentiation in the rDNA-RFLP was also high. Three out of 22 restriction site variants were found to be fixed in the nuclear rDNA arrays of hundreds of copies in either one of the two island populations. These intensive inter-populational differences indicate that the two island populations may have been isolated for a considerable period of evolutionary time, probably several millions of years, despite there having been several opportunities for renewed genetic contact during the Pleistocene ice ages. Our data strongly suggest that the current taxonomic status of the populations of the two islands, Amami-oshima and Tokuno-shima, which regards them conspecific, should be reviewed.