三叶悬钩子自然居群遗传多样性的ISSR分析

Genetic Diversity in the Natural Populations of Rubus delavayi Demonstrated by Inter-simple Sequence Repeats

利用ISSR分子标记对云南特有植物三叶悬钩子(Rubus delavayi Fanch.)的12个居群共248个个体进行了遗传多样性分析。结果表明:16个ISSR引物共扩增到199个位点,其中185个是多态性位点,占92.96%。三叶悬钩子居群具有很高的遗传多样性水平,在物种水平上平均每个位点的多态位点百分率(PPB)为97.99%,有效等位基因数(Ae)为1.427,Nei’s遗传多样性(H)为0.267,Shannon’s多态信息指数(I)为0.417;在居群水平上PPB为62.10%,Ae为1.289,H为0.177,I为0.275。居群间基因分化系数Gst=0.3351,与AMOVA分析的居群间遗传变异量占总量的33.03%相近,说明三叶悬钩子居群间存在一定程度的遗传分化。居群间遗传分化占总遗传变异的33.51%,居群内的遗传变异为66.49%,基因流(Nm)为0.9923。通过Mantel检测,居群间的遗传距离与地理距离不存在相关性。UMPGA聚类分析和二维主成分分析(PCA)结果一致。导致居群内高遗传变异水平原因主要是有限的基因流,而居群间较低的遗传多样性水平可能与生态破坏和生物入侵有关。

Genetic diversity of 248 individuals from 12 natural populations of Rubus delavayi Fanch.,which are specific but endangered species in Yunnan,was assessed using ISSR markers. The results showed that 199 amplified bands were got in PCR when sixteen primers were used. Among those bands,185（92.96% of the total bands）were polymorphic. A high level of genetic diversity was showed in these populations. At species level,percentage of polymorphic loci（PPB）was 97.99%,effective number of alleles（Ae）was 1.427,Nei’s gene diversity（H）was 0.267,and Shannon’s information index（I）was 0.417. At population level,PPB was 62.10%,Ae was 1.289,H was 0.177,I was 0.275. The level of genetic differentiation between populations was lower than that within populations. The coefficient of gene differentiation（Gst）betweenthe populations was 0.3351. And the gene differentiation contributed to 33.51% of the total genetic variations between the populations and to 66.49% within the populations. The total gene flow（Nm）was 0.9923. There was no significant correlation between genetic and geographic distances among population（r = 0.0286,P = 0.5240）in the Mantel test. The result of UPGMA clustering analysis was basically similar to that of the principle coordinate analysis（PCA）. The high genetic variation level within populations could be caused mainly by the significant genetic variation inside a population together with the limited gene flow（Nm = 0.9923）between populations. While the lower genetic diversity among the populations could be caused by severely destroyed and biological invasion of Eupatorium adenophorum Spreng.