Molecular phylogeography and evolutionary history of Picea likiangensis in the Qinghai-Tibetan Plateau inferred from mitochondrial and chloroplast DNA sequence variation  

作　　者：Jia-Bin ZOU Xiao-Li PENG Long LI Jian-Quan LIU Georg MIEHE Lars OPGENOORTH 

机构地区：[1]Molecular Ecology Group,State Key Laboratory of Grassland Agro-Ecosystem,College of Life Science,Lanzhou University,Lanzhou 730000,China [2]Faculty of Biology&Geology,University of Marburg,35032 Marburg,Germany

出　　处：《Journal of Systematics and Evolution》2012年第4期341-350,共10页植物分类学报（英文版）

基　　金：Acknowledgements The authors thank Richard ABBOTT （School of Biology, University of St Andrews, St Andrews, UK） and Richard MILNE （Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh, UK） for comments on a previous version of the manuscript. The field explorations were aided by Qin WANG （State Key Laboratory of Grassland Agro-Ecosystem, College of Life Science, Lanzhou University, Lanzhou, China） and Shi-Long CHEN and Shen-Yun CHEN （Laboratory of Qinhai-Tibet Biologi- cal Evolution and Adaptation, Northwest Plateau Insti- tute of Biology, Chinese Academy of Sciences, Xin- ing, China）. This research was supported by grants from the National Natural Science Foundation of China （30930072 and 40972018）, the Key Project of Interna- tional Collaboration Program, the Ministry of Science and Technology of China （2010DFB63500）, and the International Collaboration ＇111＇ Project （to JQL）.

摘　　要：The aim of the present study was to examine the phylogeographic and evolutionary history of Picea lildangensis, a dominant species of the conifer forests in the eastern declivity of the Qinghai-Tibetan Plateau. We collected 422 individuals from 42 natural populations of three major varieties classified under this species. In conifers, mitochondrial （mt） DNA and chloroplast （cp） DNA dispersed by seeds or pollen experience very different levels of gene flow. To this end, we examined the sequence variation of two mtDNA fragments （had5 intron 1 and nadl intron b/c） and three cpDNA fragments （trnL-trnF, trnS-trnG and nadhK/C）. We found that cpDNA probably introgressed from P. purpurea into remote populations of P. likiangensis through long-distance dispersal. Multiple refugia seem to have been maintained for P. likiangensis during the Last Glacial Maximum because the cpDNA and mtDNA haplotypes recovered were fixed in the different regions. Postglacial expansions were only detected at the distributional edges of this species where a single cpDNA or mtDNA haplotype was fixed in adjacent populations. However, genetic imprints of postglacial expansions from these two sets of markers were different in the western and southeastern regions, which may result from the long-distance dispersal of the cpDNA, as well as its fast lineage sorting during intraspecific divergences. Analysis of molecular variance further suggested that genetic differentiation between the three varieties is higher at cpDNA markers than at mtDNA markers, which supports the previous viewpoint that cpDNA markers with a high rate of gene flow may be more effective in delimitating closely related taxa. Together, the results of the present study highlight the evolutionary complexity of a widely distributed species owing to interactions among local and edge expansion, long-distance dispersal, and intraspecific divergences at two sets of DNA genomes with different rates of gene flow.The aim of the present study was to examine the phylogeographic and evolutionary history of Picea lildangensis, a dominant species of the conifer forests in the eastern declivity of the Qinghai-Tibetan Plateau. We collected 422 individuals from 42 natural populations of three major varieties classified under this species. In conifers, mitochondrial （mt） DNA and chloroplast （cp） DNA dispersed by seeds or pollen experience very different levels of gene flow. To this end, we examined the sequence variation of two mtDNA fragments （had5 intron 1 and nadl intron b/c） and three cpDNA fragments （trnL-trnF, trnS-trnG and nadhK/C）. We found that cpDNA probably introgressed from P. purpurea into remote populations of P. likiangensis through long-distance dispersal. Multiple refugia seem to have been maintained for P. likiangensis during the Last Glacial Maximum because the cpDNA and mtDNA haplotypes recovered were fixed in the different regions. Postglacial expansions were only detected at the distributional edges of this species where a single cpDNA or mtDNA haplotype was fixed in adjacent populations. However, genetic imprints of postglacial expansions from these two sets of markers were different in the western and southeastern regions, which may result from the long-distance dispersal of the cpDNA, as well as its fast lineage sorting during intraspecific divergences. Analysis of molecular variance further suggested that genetic differentiation between the three varieties is higher at cpDNA markers than at mtDNA markers, which supports the previous viewpoint that cpDNA markers with a high rate of gene flow may be more effective in delimitating closely related taxa. Together, the results of the present study highlight the evolutionary complexity of a widely distributed species owing to interactions among local and edge expansion, long-distance dispersal, and intraspecific divergences at two sets of DNA genomes with different rates of gene flow.

关 键 词：chloroplast DNA genetic differentiation INTROGRESSION mitochondrial DNA PHYLOGEOGRAPHY Picea likiangensis REFUGIA 

分 类 号：Q959.468[生物学—动物学] S512.101[农业科学—作物学]