Original Research ARTICLE
Deep intraspecific divergence in Lancea tibetica (Mazaceae) distributed over the Qinghai-Tibetan Plateau
- 1Northwest Institute of Plateau Biology (CAS), China
- 2University of Chinese Academy of Sciences (UCAS), China
- 3Qinghai Province Key Laboratory of Crop Molecular Breeding, China
Qinghai-Tibetan Plateau (QTP) is an important biodiversity hub, which is very sensitive to climate change. Here in this study, we investigated genetic diversity and past population dynamics of Lancea tibetica (Mazaceae), an endemic herb to QTP and adjacent highlands. We sequenced chloroplast and nuclear ribosomal DNA fragments for 429 individuals, collected from 29 localities, covering their major distribution range at the QTP. A total of 19 chloroplast haplotypes and 13 nuclear genotypes in two well-differentiated lineages, corresponding to populations into two groups isolated by Tanggula and Bayangela Mountains. Meanwhile, significant phylogeographical structure was detected among sampling range of L. tibetica, and 61.50% of genetic variations was partitioned between groups. Gene flow across the whole region appears to be restricted by high mountains, suggesting a significant role of geography in the genetic differences between the two groups. Divergence time between the two lineages dated to 8.63 million years ago, which corresponded to the uplifting of QTP during the late Miocene and Pliocene. Ecological differences were found between both the lineages represent species-specific characteristics, sufficient to keep the lineages separated to a high degree. The simulated distribution from the last interglacial period to the current period showed that the distribution of L. tibetica experienced shrinkage and expansion. Climate changes during the Pleistocene glacial-interglacial cycles had a dramatic effect on L. tibetica distribution ranges. Multiple refugia of L. tibetica might have remained during the species history, to south of the Tanggula and north of Bayangela Mountains, both appeared as topological barrier and contributed to restricting gene flow between the two lineages. Together, geographic isolation and climatic factors have played a fundamental role in promoting diversification and evolution of L. tibetica.
Keywords: Qinghai-Tibetan Plateau, Lancea tibetica, population genetic structure, Phylogeography, Demography, divergence
Received: 12 Jun 2018;
Accepted: 03 Oct 2018.
Edited by:Kangshan Mao, Sichuan University, China
Reviewed by:Peng Zhao, Northwest University, China
Jian-Wen Zhang, Kunming Institute of Botany (CAS), China
Copyright: © 2018 Xia, Tian, Zhang, Khan, Gao, Xing, Zhang, Yu and Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Dr. Faqi Zhang, Northwest Institute of Plateau Biology (CAS), Xining, China, email@example.com
Prof. Shilong Chen, Northwest Institute of Plateau Biology (CAS), Xining, China, firstname.lastname@example.org