A Phylogeographic Survey of the Pygmy Mouse Mus minutoides in South Africa: Taxonomic and Karyotypic Inference from Cytochrome b Sequences of Museum Specimens
A Phylogeographic Survey of the Pygmy Mouse Mus minutoides in South Africa: Taxonomic and Karyotypic Inference from Cytochrome b Sequences of Museum Specimens
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DOI：
10.1371/journal.pone.0098499
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发表时间：
2014-06-06
期刊：
影响因子：
3.7
通讯作者：
Britton-Davidian, Janice
中科院分区：
文献类型：
--
作者：
Chevret, Pascale;Robinson, Terence J.;Britton-Davidian, Janice
非洲侏儒鼠（Mus，Nannomys亚属）是一组广泛分布于撒哈拉以南非洲的小型啮齿动物。这一组内的染色体多样性是广泛的，许多研究表明核型是一个有用的分类标记。这与南非的Mus minutoides种群有关，其中记录了两种不同的细胞型（2n = 34，2n = 18）和性别决定系统的修改（由于某些雌性中存在Y染色体）。这种染色体多样性反映在线粒体DNA序列上，这些序列明确区分了不同的侏儒小鼠物种，重要的是，不同的M。微小细胞型然而，南非侏儒鼠种群的地理划界和分类学知之甚少。为了解决这个问题，组织样本的M。minutoides从六个南非博物馆收藏的标本中取出并进行分析。部分细胞色素B序列（400 pB），成功地从44%的154个样品处理扩增。鉴定出两种：M. indutus和M.微小体M. indutus样本提供了两个意想不到的功能：i）细胞色素B基因的核副本中检测到许多标本，和ii）该物种的范围被发现扩展到相当远的南部比目前所理解的。对M. minutoides样本揭示了两个很好的支持分支：一个南部的分支，其中包括两个染色体组先前在南非确定，和东部的分支，从东非延伸到南非。一致的分子系统发育和染色体数据集允许在不同的分支博物馆标本的暂定染色体分配，以及错误的博物馆标本的纠正。
The African pygmy mice (Mus, subgenus Nannomys) are a group of small-sized rodents that occur widely throughout sub-Saharan Africa. Chromosomal diversity within this group is extensive and numerous studies have shown the karyotype to be a useful taxonomic marker. This is pertinent to Mus minutoides populations in South Africa where two different cytotypes (2n = 34, 2n = 18) and a modification of the sex determination system (due to the presence of a Y chromosome in some females) have been recorded. This chromosomal diversity is mirrored by mitochondrial DNA sequences that unambiguously discriminate among the various pygmy mouse species and, importantly, the different M. minutoides cytotypes. However, the geographic delimitation and taxonomy of pygmy mice populations in South Africa is poorly understood. To address this, tissue samples of M. minutoides were taken and analysed from specimens housed in six South African museum collections. Partial cytochrome b sequences (400 pb) were successfully amplified from 44% of the 154 samples processed. Two species were identified: M. indutus and M. minutoides. The sequences of the M. indutus samples provided two unexpected features: i) nuclear copies of the cytochrome b gene were detected in many specimens, and ii) the range of this species was found to extend considerably further south than is presently understood. The phylogenetic analysis of the M. minutoides samples revealed two well-supported clades: a Southern clade which included the two chromosomal groups previously identified in South Africa, and an Eastern clade that extended from Eastern Africa into South Africa. Congruent molecular phylogenetic and chromosomal datasets permitted the tentative chromosomal assignments of museum specimens within the different clades as well as the correction of misidentified museum specimens.