Abstract
Quaternary climatic factors have played a significant role in population divergence and demography. Here we investigated the phylogeography of Osteomeles schwerinae, a dominant riparian plant species of the hot/warm-dry river valleys of the Hengduan Mountains (HDM), Qinling Mountains (QLM) and Yunnan-Guizhou Plateau (YGP). Three chloroplast DNA (cpDNA) regions (trnD-trnT, psbD-trnT, petL-psbE), one single copy nuclear gene (glyceraldehyde 3-phosphate dehydrogenase; G3pdh), and climatic data during the Last Interglacial (LIG; c. 120–140 ka), Last Glacial Maximum (LGM; c. 21 ka), and Current (c. 1950–2000) periods were used in this study. Six cpDNA haplotypes and 15 nuclear DNA (nDNA) haplotypes were identified in the 40 populations of O. schwerinae. Spatial Analysis of Molecular Variance, median-joining networks, and Bayesian phylogenetic trees based on the cpDNA and nDNA datasets, all suggested population divergence between the QLM and HDM-YGP regions. Our climatic analysis identified significant heterogeneity of the climatic factors in the QLM and HDM-YGP regions during the aforementioned three periods. The divergence times based on cpDNA and nDNA haplotypes were estimated to be 466.4–159.4 ka and 315.8–160.3 ka, respectively, which coincide with the time of the weakening of the Asian monsoons in these regions. In addition, unimodal pairwise mismatch distribution curves, expansion times, and Ecological Niche Modeling suggested a history of population expansion (rather than contraction) during the last glaciation. Interestingly, the expansion times were found being well consistent with the intensification of the Asian monsoons during this period. We inferred that the divergence between the two main lineages is probably caused by disruption of more continuous distribution because of weakening of monsoons/less precipitation, whilst subsequent intensification of the Asian monsoons during the last glaciation facilitated the expansion of O. schwerinae populations.
Highlights
Exploring factors associated with population processes is an important issue in ecology and evolution [1,2,3,4]
A considerable number of phylogeographic studies have been conducted in the Hengduan Mountains (HDM) and adjacent regions [e.g. the Qinghai-Tibetan Plateau (QTP); Eastern Himalayas (EH); Yunnan-Guizhou Plateau (YGP); Qinling Mountains (QLM); Fig 1]
In the Spatial Analysis of Molecular Variance (SAMOVA) analysis based on chloroplast DNA (cpDNA) sequences, two groups corresponding to the QLM and HDM-YGP regions were well defined when K = 2
Summary
Exploring factors associated with population processes (e.g. population divergence and demography) is an important issue in ecology and evolution [1,2,3,4]. A considerable number of phylogeographic studies have been conducted in the Hengduan Mountains (HDM) and adjacent regions [e.g. the Qinghai-Tibetan Plateau (QTP); Eastern Himalayas (EH); Yunnan-Guizhou Plateau (YGP); Qinling Mountains (QLM); Fig 1]. These studies provide robust molecular evidence that (sub)alpine plants presently occurring in these regions are strongly affected by glacial-interglacial climatic fluctuations during the Quaternary [8,9,10,11,12,13,14]. In comparison to studies of (sub)alpine plants, few riparian plants of hot/warm-dry river valleys in these regions have been studied. The phylogeographic studies of riparian plants conducted so far have focused on two species: Terminalia franchetii (Combretaceae) and Buddleja crispa (Buddlejaceae), both of which indicated that the discontinuous distribution patterns of these plants are strongly linked to historical drainage re-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
