Multilocus analysis of nucleotide variation and speciation in three closely related Populus (Salicaceae) species.
Historical tectonism and climate oscillations can isolate and contract the geographical distributions of many plant species, and they are even known to trigger species divergence and ultimately speciation. Here, we estimated the nucleotide variation and speciation in three closely related Populus species, Populus tremuloides, P. tremula and P. davidiana, distributed in North America and Eurasia. We analysed the sequence variation in six single-copy nuclear loci and three chloroplast (cpDNA) fragments in 497 individuals sampled from 33 populations of these three species across their geographic distributions. These three Populus species harboured relatively high levels of nucleotide diversity and showed high levels of nucleotide differentiation. Phylogenetic analysis revealed that P. tremuloides diverged earlier than the other two species. The cpDNA haplotype network result clearly illustrated the dispersal route from North America to eastern Asia and then into Europe. Molecular dating results confirmed that the divergence of these three species coincided with the sundering of the Bering land bridge in the late Miocene and a rapid uplift of the Qinghai-Tibetan Plateau around the Miocene/Pliocene boundary. Vicariance-driven successful allopatric speciation resulting from historical tectonism and climate oscillations most likely played roles in the formation of the disjunct distributions and divergence of these three Populus species.
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.|College of Forestry, Shandong Agriculture University, Taian, Shandong Province, 271000, China.
Shuhui
S
Du
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.|Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu Province, 210000, China.
Zhaoshan
Z
Wang
Department of Ecology and Environmental Science, Umeå Plant Science Centre, Umeå University, Umeå, 90187, Sweden.
Pär K
PK
Ingvarsson
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.
Dongsheng
D
Wang
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.
Junhui
J
Wang
Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.
Zhiqiang
Z
Wu
Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.
Luke R
LR
Tembrock
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.|Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu Province, 210000, China.
Jianguo
J
Zhang
D018742:DNA, Chloroplast / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D005819:Genetic Markers; D049810:Genetic Speciation; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D032107:Populus / Q000145:classification* / Q000235:genetics; D017422:Sequence Analysis, DNA
D018742:DNA, Chloroplast; D018744:DNA, Plant; D005819:Genetic Markers
Populus; nucleotide differentiation; nucleotide variation; speciation; vicariance