作 者：Shuhui Du, Zhaoshan Wang, Ingvarsson P K, Dongsheng Wang, Junhui Wang,
Zhiqiang Wu, Luke R. Tembrock and Jianguo Zhang*
期 刊：Molecular ecology
发表时间：2015年
卷.期.页码：24(19):4994-5005
摘要：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.
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