title: Effect of Yangtze River on population genetic structure of the relict plant Parrotia subaequalis in eastern China.
abstract: Parrotia subaequalis (Hamamelidaceae) is a Tertiary relic species endemic in eastern China. We used inter-simple sequence repeat (ISSR) markers to access genetic diversity and population genetic structure in natural five populations of P. subaequalis. The levels of genetic diversity were higher at species level (H = 0.2031) but lower at population level (H = 0.1096). The higher genetic diversity at species levels might be attributed to the accumulation of distinctive genotypes which adapted to the different habitats after Quaternary glaciations. Meanwhile, founder effects on the early stage, and subsequent bottleneck of population regeneration due to its biological characteristics, environmental features, and human activities, seemed to explain the low population levels of genetic diversity. The hierarchical AMOVA revealed high levels (42.60%) of among-population genetic differentiation, which was in congruence with the high levels of Nei's genetic differentiation index (G ST = 0.4629) and limited gene flow (N m = 0.5801) among the studied populations. Mantel test showed a significant isolation-by-distance, indicating that geographic isolation has a significant effect on genetic structure in this species. Unweighted pair-group method with arithmetic average clustering, PCoA, and Bayesian analyses uniformly recovered groups that matched the geographical distribution of this species. In particular, our results suggest that Yangtze River has served as a natural barrier to gene flow between populations occurred on both riversides. Concerning the management of P. subaequalis, the high genetic differentiation among populations indicates that preserving all five natural populations in situ and collecting enough individuals from these populations for ex situ conservation are necessary.
authors.affiliation: College of Life Sciences Nanjing University 22 Hankou Road Nanjing 210093 China ; State Key Laboratory of Pharmaceutical Biotechnology Nanjing University 22 Hankou Road Nanjing 210093 China.
authors.forename: Qifang
authors.initials: Q
authors.lastname: Geng
authors.affiliation: College of Life Sciences Nanjing University 22 Hankou Road Nanjing 210093 China ; Wetland Conservation Station of Jiangsu Province 22 Dinghuaimen Street Nanjing 210036 China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Yao
authors.affiliation: College of Life Sciences Nanjing University 22 Hankou Road Nanjing 210093 China ; State Key Laboratory of Pharmaceutical Biotechnology Nanjing University 22 Hankou Road Nanjing 210093 China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.affiliation: College of Life Sciences Nanjing University 22 Hankou Road Nanjing 210093 China ; State Key Laboratory of Pharmaceutical Biotechnology Nanjing University 22 Hankou Road Nanjing 210093 China.
authors.forename: Jia
authors.initials: J
authors.lastname: He
authors.affiliation: College of Life Sciences Nanjing University 22 Hankou Road Nanjing 210093 China ; State Key Laboratory of Pharmaceutical Biotechnology Nanjing University 22 Hankou Road Nanjing 210093 China.
authors.forename: Danbi
authors.initials: D
authors.lastname: Wang
authors.affiliation: College of Life Sciences Nanjing University 22 Hankou Road Nanjing 210093 China ; State Key Laboratory of Pharmaceutical Biotechnology Nanjing University 22 Hankou Road Nanjing 210093 China.
authors.forename: Zhongsheng
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Earth and Environment International Center for Tropical Botany Florida International University Miami FL 33199 USA ; College of Forestry Guangxi University Nanning 530004 China.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
keywords: Genetic structure; ISSR; Parrotia subaequalis; Yangtze River; relict plant