Mitochondrial and chloroplast phylogeography of Picea crassifolia Kom. (Pinaceae) in the Qinghai‐Tibetan Plateau and adjacent highlands
Mitochondrial and chloroplast phylogeography of Picea crassifolia Kom. (Pinaceae) in the Qinghai‐Tibetan Plateau and adjacent highlands
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DOI：
10.1111/j.1365-294x.2007.03459.x
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发表时间：
2007-10
影响因子：
4.9
通讯作者：
L. Meng;Rui Yang;R. Abbott;G. Miehe;Tianhua Hu;Jianquan Liu
中科院分区：
文献类型：
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作者：
L. Meng;Rui Yang;R. Abbott;G. Miehe;Tianhua Hu;Jianquan Liu
在这项研究中，我们研究了优势森林物种云杉（Picea crassifolia Kom）母系遗传的线粒体DNA （nad1内含子b/c和nad5内含子1）和父系遗传的叶绿体DNA （trnC - trnD）序列变异。在对32个种群的442个个体的调查中，我们发现了9种有丝分裂型和2种叶绿体。检测到显著的线粒体DNA群体细分（GST = 0.512; NST = 0.679），表明群体间存在低水平的种子循环基因流动和显著的系统地理结构（NST > GST, P < 0.05）。高原物种的单倍型序列与邻近高原物种的单倍型序列不同，表明在第四纪冰川时期，两个地区的物种之间存在着长时间的异域破碎化，并且每个地区都存在着独立的避难所。在QTP平台上，除1个分离群体外，其余所有被调查群体均为固定的有丝分裂型，而高原边缘的大多数群体包含不止一个单倍型，高原平台群体中固定的有丝分裂型经常出现。这种分布模式表明，目前QTP平台上的分离种群经历了共同的再殖民化历史。然而，在父系遗传的叶绿体DNA单倍型中没有检测到相同的系统地理模式。两种叶绿体分布在整个物种范围内，地理种群分化较小（GST = NST = 0.093）。这为花粉介导的基因在孤立的森林斑块之间高效流动提供了证据，无论是在QTP种群内部还是在邻近的高原种群之间。考虑到腾格里沙漠在过去大约180万年中一直是这两个地区之间的地理屏障，QTP和邻近高地上的森林之间缺乏花粉介导的基因流动是令人惊讶的。
The disjunct distribution of forests in the Qinghai‐Tibetan Plateau (QTP) and adjacent Helan Shan and Daqing Shan highlands provides an excellent model to examine vegetation shifts, glacial refugia and gene flow of key species in this complex landscape region in response to past climatic oscillations and human disturbance. In this study, we examined maternally inherited mitochondrial DNA (nad1 intron b/c and nad5 intron 1) and paternally inherited chloroplast DNA (trnC‐trnD) sequence variation within a dominant forest species, Picea crassifolia Kom. We recovered nine mitotypes and two chlorotypes in a survey of 442 individuals from 32 populations sampled throughout the species’ range. Significant mitochondrial DNA population subdivision was detected (GST = 0.512; NST = 0.679), suggesting low levels of recurrent gene flow through seeds among populations and significant phylogeographical structure (NST > GST, P < 0.05). Plateau haplotypes differed in sequence from those in the adjacent highlands, suggesting a long period of allopatric fragmentation between the species in the two regions and the presence of independent refugia in each region during Quaternary glaciations. On the QTP platform, all but one of the disjunct populations surveyed were fixed for the same mitotype, while most populations at the plateau edge contained more than one haplotype with the mitotype that was fixed in plateau platform populations always present at high frequency. This distribution pattern suggests that present‐day disjunct populations on the QTP platform experienced a common recolonization history. The same phylogeographical pattern, however, was not detected for paternally inherited chloroplast DNA haplotypes. Two chlorotypes were distributed throughout the range of the species with little geographical population differentiation (GST = NST = 0.093). This provides evidence for highly efficient pollen‐mediated gene flow among isolated forest patches, both within and between the QTP and adjacent highland populations. A lack of isolation to pollen‐mediated gene flow between forests on the QTP and adjacent highlands is surprising given that the Tengger Desert has been a geographical barrier between these two regions for approximately the last 1.8 million years.