Wang Xin-Hui, Li Jie, Zhang Li-Min, He Zi-Wen, Mei Qi-Ming, Gong Xun, Jian Shu-Guang
Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.
Front Genet. 2019 Dec 23;10:1238. doi: 10.3389/fgene.2019.01238. eCollection 2019.
Historical geology, climatic oscillations, and seed dispersal capabilities are thought to influence the population dynamics and genetics of plants, especially for distribution-restricted and threatened species. Investigating the genetic resources within and among taxa is a prerequisite for conservation management. The complex consists of six endangered species that are endemic to South China. In this study, we investigated the relationship between phylogeographic history and the genetic structure of the complex. To estimate the phylogeographic history of the complex, we assessed the genetic structure and divergence time, and performed phylogenetic and demographic historical analyses. Two chloroplast DNA intergenic regions (cpDNA), two single-copy nuclear genes (SCNGs), and six microsatellite loci (SSR) were sequenced for 18 populations. The SCNG data indicated a high genetic diversity within populations, a low genetic diversity among populations, and significant genetic differentiation among populations. Significant phylogeographical structure was detected. Structure and phylogenetic analyses both revealed that the 18 populations of the complex have two main lineages, which were estimated to diverge in the Middle Pleistocene. We propose that was incorporated into and that the other populations, which are mainly located on Hainan Island, merged into one lineage. Bayesian skyline plot analyses revealed that the complex experienced a recent decline, suggesting that the complex probably experienced a bottleneck event. We infer that the genetic structure of the complex has been affected by Pleistocene climate shifts, sea-level oscillations, and human activities. In addition to providing new insights into the evolutionary legacy of the genus, the genetic characterizations will be useful for the conservation of species.
历史地质学、气候振荡和种子传播能力被认为会影响植物的种群动态和遗传学，尤其是对于分布受限和受威胁的物种。研究类群内部和之间的遗传资源是保护管理的先决条件。该复合体由六种中国南方特有的濒危物种组成。在本研究中，我们调查了该复合体的系统发育历史与遗传结构之间的关系。为了估计该复合体的系统发育历史，我们评估了遗传结构和分歧时间，并进行了系统发育和种群历史分析。对18个种群的两个叶绿体DNA基因间隔区（cpDNA）、两个单拷贝核基因（SCNG）和六个微卫星位点（SSR）进行了测序。SCNG数据表明种群内遗传多样性高，种群间遗传多样性低，且种群间存在显著的遗传分化。检测到显著的系统地理结构。结构和系统发育分析均表明，该复合体的18个种群有两个主要谱系，估计在中更新世发生分歧。我们提出，[具体物种A]被并入[具体物种B]，而其他主要位于海南岛的种群合并为一个谱系。贝叶斯天际线图分析表明，该复合体近期数量下降，这表明该复合体可能经历了瓶颈事件。我们推断，该复合体的遗传结构受到更新世气候变化、海平面振荡和人类活动的影响。除了为该属的进化遗产提供新的见解外，这些遗传特征对于[具体物种]的保护也将是有用的。
