More introgression with less gene flow: chloroplast vs. mitochondrial DNA in the Picea asperata complex in China, and comparison with other Conifers
More introgression with less gene flow: chloroplast vs. mitochondrial DNA in the Picea asperata complex in China, and comparison with other Conifers
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DOI：
10.1111/j.1365-294x.2009.04107.x
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发表时间：
2009-04-01
影响因子：
4.9
通讯作者：
Liu, Jian Quan
中科院分区：
文献类型：
--
作者：
Du, Fang K.;Petit, Remy J.;Liu, Jian Quan
最近的研究表明，渗入的速度应该是负相关的基因流的水平，因为渗入的人口不能“拯救”种内基因流，如果它太低。线粒体和叶绿体DNA（mtDNA和叶绿体DNA）的经验非常不同的水平的基因流在针叶树，由于其对比的母亲和父亲的传输模式，因此预测，mtDNA应该更容易渗入比叶绿体DNA在这组。在这里，我们使用线粒体DNA和叶绿体DNA的序列数据来测试这一假设在一组密切相关的云杉物种，云杉复杂的中国。从云杉复合体5个种46个自然居群的459个个体中回收了9种线粒体和9种叶绿体单倍型。两个mtDNA内含子沿着变异较小，群体间分化程度较高（G（ST）= 0.90）。与此相反，我们检测到较高的变异和较低的分化种群之间的cpDNA标记（G（ST）= 0.56），目前为止，大多数针叶树种研究的趋势。我们发现，cpDNA的变化，虽然远远不能完全诊断，是物种特异性比mtDNA的变化：四组人口被确定使用cpDNA标记，所有这些都涉及到物种或物种组，而mtDNA，地理变异压倒物种分化。文献表明，线粒体DNA单倍型往往是共享的针叶树物种之间的关系，而cpDNA单倍型是更具体的物种。因此，种内基因流动的增加似乎会减少物种内的分化，但不会减少物种间的分化。
Recent work has suggested that rates of introgression should be inversely related to levels of gene flow because introgressed populations cannot be 'rescued' by intraspecific gene flow if it is too low. Mitochondrial and chloroplast DNA (mtDNA and cpDNA) experience very different levels of gene flow in conifers due to their contrasted maternal and paternal modes of transmission, hence the prediction that mtDNA should introgress more readily than cpDNA in this group. Here, we use sequence data from both mtDNA and cpDNA to test this hypothesis in a group of closely related spruces species, the Picea asperata complex from China. Nine mitochondrial and nine chloroplast haplotypes were recovered from 459 individuals in 46 natural populations belonging to five species of the Picea asperata complex. Low variation was found in the two mtDNA introns along with a high level of differentiation among populations (G(ST) = 0.90). In contrast, we detected higher variation and lower differentiation among populations at cpDNA markers (G(ST) = 0.56), a trend shared by most conifer species studied so far. We found that cpDNA variation, although far from being fully diagnostic, is more species-specific than mtDNA variation: four groups of populations were identified using cpDNA markers, all of them related to species or groups of species, whereas for mtDNA, geographical variation prevails over species differentiation. The literature suggests that mtDNA haplotypes are often shared among related conifer species, whereas cpDNA haplotypes are more species-specific. Hence, increased intraspecific gene flow appears to decrease differentiation within species but not among species.