Phylogeography and genetic variation in the South American rodent Tympanoctomys barrerae (Rodentia: Octodontidae)
Phylogeography and genetic variation in the South American rodent Tympanoctomys barrerae (Rodentia: Octodontidae)
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DOI：
10.1644/09-mamm-a-177.1
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发表时间：
2010-04
期刊：
影响因子：
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通讯作者：
A. Ojeda
中科院分区：
文献类型：
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作者：
A. Ojeda
红鼠（Tympanoctomys barrerae）是阿根廷中西部和南部干旱地区特有的一种八齿类啮齿动物。它是孤独的，生活在软土中建造的复杂洞穴中，在蒙特和巴塔哥尼亚沙漠低地栖息地与盐盆地和沙丘相关的斑块中以低种群密度出现。本研究的目的是调查这种沙漠专家的遗传结构和生物地理。为了评估遗传变异，对来自8个地点的60个个体的线粒体控制区800碱基对片段进行了测序。单倍型之间的关系是通过系统发育分析（最大简约、贝叶斯和网络）推断出来的。采用描述性统计、错配分布、中性检验（Tajima’s和Fu’s）和分子方差分析（AMOVAs）分析遗传结构和人口统计学历史。总共发现了26个单倍型，大多数局限于单个种群。未共享单倍型的存在与低迁移率一致。在29°S ~ 39°S范围内，南部和北部居群的遗传多样性值高于中部居群。以中心居群的单倍型为基础，barrera居群表现出中等到高度的遗传分化。AMOVA分析表明，所有种群的地理结构均为中等水平。中心种群的低单倍型和核苷酸多样性表明，在这部分鼠的活动范围内，可能存在与更新世冰川或火山活动有关的瓶颈。系统地理结构中等，分析恢复了2个主要分支：A（中部和部分南部分布）和B（北部和部分南部分布）。大多数种群是多系的，表明它们还没有被隔离足够长的时间达到相互单系。对进化支A和进化支B进行的人口统计分析表明，进化支A和进化支B最近有人口扩张的历史。
Abstract The red viscacha rat, Tympanoctomys barrerae, is an octodontid rodent endemic to the arid west-central and southern regions of Argentina. It is solitary, lives in complex burrows built in soft soil, and occurs at low population densities in patches associated with salt basins and sand dunes in lowland habitats of the Monte and Patagonia deserts. The purpose of this study was to investigate the genetic structure and biogeography of this desert specialist. To assess genetic variation an 800-base pair fragment of the mitochondrial control region was sequenced for 60 individuals from 8 localities across the species' range. Relationships among haplotypes were inferred from phylogenetic analyses (maximum parsimony, Bayesian, and networks). Genetic structure and demographic history were analyzed with descriptive statistics, mismatch distributions, neutrality tests (Tajima's and Fu's), and analyses of molecular variance (AMOVAs). In total, 26 haplotypes were found, most restricted to single populations. The presence of unshared haplotypes was consistent with low migration rates. Within the distribution (between 29°S and 39°S) southern and northern populations showed higher genetic diversity values than central populations. Populations of T. barrerae showed moderate to high genetic differentiation on the basis of haplotypes of central populations. AMOVA analyses indicated a moderate level of geographic structure for all populations. Low haplotype and nucleotide diversities in central populations suggest a possible bottleneck associated with Pleistocene glaciations or volcanic activity in this part of the range of the viscacha rat. Phylogeographic structure was moderate, and the analyses recovered 2 principal clades: A (with central and a part of the southern distribution) and B (with northern and another part of the southern distribution). Most populations were polyphyletic, indicating that they have not been isolated long enough to reach reciprocal monophyly. Demographic analyses conducted for clades A and B suggest a recent history of population expansion.