Speciation of two desert poplar species triggered by Pleistocene climatic oscillations.
Despite the evidence that the Pleistocene climatic fluctuations have seriously affected the distribution of intraspecific diversity, less is known on its impact on interspecific divergence. In this study, we aimed to test the hypothesis that the divergence of two desert poplar species Populus euphratica Oliv. and P. pruinosa Schrenk. occurred during the Pleistocene. We sequenced 11 nuclear loci in 60 individuals from the two species to estimate the divergence time between them and to test whether gene flow occurred after species separation. Divergence time between the two species was estimated to be 0.66-1.37 million years ago (Ma), a time at which glaciation was at its maximum in China and deserts developed widely in central Asia. Isolation-with-Migration model also indicated that the two species had diverged in the presence of gene flow. We also detected evidence of selection at GO in P. euphratica and to a lesser extent at PhyB2. Together, these results underscore the importance of Pleistocene climate oscillations in triggering plant speciation as a result of habitats divergence.
State Key Laboratory of Grassland Ecosystem, College of Life Science, Lanzhou University, Lanzhou, China.
J
J
Wang
Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
T
T
Källman
State Key Laboratory of Grassland Ecosystem, College of Life Science, Lanzhou University, Lanzhou, China.
J
J
Liu
State Key Laboratory of Grassland Ecosystem, College of Life Science, Lanzhou University, Lanzhou, China.
Q
Q
Guo
State Key Laboratory of Grassland Ecosystem, College of Life Science, Lanzhou University, Lanzhou, China.
Y
Y
Wu
1] Laboratory of Evolutionary Genomics, CAS-MPG Partner Institute for Computational Biology, Chinese Academy of Sciences, Shanghai, China [2] Graduate School of the Chinese Academy of Sciences, Beijing, China.
K
K
Lin
1] Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden [2] Laboratory of Evolutionary Genomics, CAS-MPG Partner Institute for Computational Biology, Chinese Academy of Sciences, Shanghai, China.
M
M
Lascoux
D005075:Biological Evolution; D002681:China; D002980:Climate; D018742:DNA, Chloroplast / Q000235:genetics; D051456:Gene Flow; D056426:Genetic Loci; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D006239:Haplotypes; D015810:Linkage Disequilibrium; D008969:Molecular Sequence Data; D032107:Populus / Q000235:genetics*; D011995:Recombination, Genetic
D018742:DNA, Chloroplast