“国内最新相关科研成果”系列之2019年第三期
李歌，凌少军，陈伟芳，任明迅，唐亮
GE LI, SHAOJUN LING, WEIFANG CHEN, MINGXUN REN, LIANG TANG
昌化江河谷隔离对海南岛特有植物盾叶苣苔遗传多样性的影响
Effects of geographic isolation caused by Changhua River on genetic diversity of Hainan-endemic Metapetrocosmea peltata (Gesneriaceae)
广西植物 2019-01-30（网络首发）
Guihaia2019-01-30(Published in internet/CNKI)
摘要
盾叶苣苔(Metapetrocosmea peltata ( Merr. et Chun) W. T. Wang )是海南岛特有植物，分布在海南岛中南部山区。该研究采集了盾叶苣苔 11 个种群共 172 份材料，通过 PCR 扩增和测序分析核糖体转录间隔区(ITS)序列的变异式样，评估盾叶苣苔的遗传多样性与遗传分化格局，并探索影响盾叶苣苔遗传变异地理分布的因素。结果表明盾叶苣苔物种水平的遗传多样性很高(HT = 0.998, π = 0.0235)，种群间基因流很弱(Nm = 0.04)且存在强烈的遗传分化(GST =0.375)。单倍型分析显示盾叶苣苔的单倍型大多是种群特异的，仅白马岭与南茂岭种群有共享单倍型。 Mantel test 表明遗传距离和地理距离存在一定相关性(相关系数 r = 0.322， P = 0.010)。 Structure 聚类分析将盾叶苣苔划分为 6 种遗传成分，其地理分布与昌化江河谷导致的隔离样式基本一致，基于 Nei 遗传距离的种群聚类分析也支持这一结果，显示盾叶苣苔遗传多样性的分布受到昌化江河谷的隔离作用。 AMOVA 分析确定 67%的变异来自地区间，表明地理隔离是盾叶苣苔种群分化的重要因素。该研究揭示昌化江及其支流所引起的海南岛山地内部隔离是盾叶苣苔种群发生强烈遗传分化的重要原因，也导致盾叶苣苔在物种水平具有较高的遗传多样性。上述研究结果不但能对海南特有苦苣苔资 源盾叶苣苔的保护和可持续利用提供理论指导，也将有助于理解海南岛特有植物和其他海岛植物遗传变异的地理分布及其影响因素。
ABSTRACT
Metapetrocosmea peltata (Gesneriaceae) is an endemic species distributed in the middle and southern mountainousarea of Hainan Island. In this study, we collected 172 M. peltata individuals from 11 natural populations, and assessed thegenetic diversity and differentiation of this species based on sequence variation of intergenic transcribed spacer (ITS) region.In addition, the factors that may impact the level and distribution of genetic diversity were explored. The analysis revealedthat M. peltata has a high level of genetic diversity at its species level (HT = 0.998, π = 0.0235), however, the gene flowbetween populations was very weak (Nm = 0.04), whereas the genetic differentiation was quite strong (GST = 0.375). Mosthaplotypes of M. peltata were population specific, only except for the BM and NM population, which shared a fewaplotypes. Mantel test showed that the genetic distances between haplotypes were correlated with their geographic distances(correlation index r = 0.322, P = 0.010). Structure analysis clustered individuals of M. peltata into six genetic groups, whosegeographic distribution is largely concordant with the isolation pattern of Hainan mountainous area caused by ChanghuaRiver. The geographic distribution of genetic clusters was further supported by population cluster analysis based on Nei’sgenetic distance. This study manifests the isolation effect of Changhua River on the distribution of genetic diversity of M. peltata. AMOVA showed that 67% genetic variation was partitioned among populations, suggesting genetic differentiation ofthis species was mainly caused by geographic isolation. In conclusion, geographic isolation of Hainan mountainous areacaused by Changhua River and its tributaries should be the driving force for the strong genetic differen tiation among M. peltata populations, and also may lead to the high genetic diversity detected at the species level of M. peltata. This study notonly provides recommendation for efficient conservation and utilization of M. peltata, a potential ornamental plant species,but also facilitates the understanding of geographic distribution of genetic variation for Hainan Island endemic and other plantspecies.
原文链接（Original article link）：
http://kns.cnki.net/kcms/detail/45.1134.q.20190128.1718.006.html
Fig.1 The constitution and geographical distribution of haplotypes of studied M. peltata populations.
Fig.2 M. peltata haplotype network constructed based on ITS sequence variation.
Fig. 3 (A) DeltaK plotting; (B) Distribution of cluster memberships at population level when K =6.
Fig. 4 Population tree based on Nei’s genetic distance to illustrate the relationship among 11 populations of M. peltata.
