Chen X H, Gao Y B
Department of Plant Biology and Ecology, College of Life Science, Nankai University, Tianjin 300071, China.
Genetika. 2011 Sep;47(9):1196-203.
Genetic variability in random amplified polymorphic DNA (RAPD) was studied in 90 individuals of Caragana microphylla, an outcrossing perennial shrub species, from five natural populations sampled in Inner Mongolia steppe of China on a small scale. Nineteen selected primers were used to amplify DNA samples, and totally 225 bands were detected. The percentage of polymorphic bands within populations ranged form 58.22% to 63.56%, with an average of 60% at the population level and 71.11% at the species level, indicating relatively high genetic variations in C. microphylla species. Shannon's information index (I) and Nei's gene diversity (h) showed the similar trend with each other. According to the analysis of Nei's gene diversity, the percentage of genetic variation among populations was 7.13%, indicating a low level of genetic differentiation among populations. There existed a strong gene flow (Nm = 3.26) among populations. Although AMOVA analysis also revealed most variation was within populations (phi(ST) = 4.1%), a significant proportion was observed among populations (P<0.001) in the present study, suggesting genetic differentiation occurred among populations at a certain extent. Based on Mantel's tests and the results of previous studies, the genetic structure pattern of C. microphylla accorded with the isolation-by-distance model on a very large scale, however, on a small scale, the significant genetic differentiation among populations might be enhanced by the micro-environmental divergence among the sampling sites, rather than by geographic factors. Analysis of the genetic variations of C. microphylla populations provided useful information for the adaptive strategy of Caragana species.
在中国内蒙古草原小规模采集的5个天然种群中，对90株小叶锦鸡儿（一种异交多年生灌木物种）个体的随机扩增多态性DNA（RAPD）遗传变异性进行了研究。使用19条选定的引物对DNA样本进行扩增，共检测到225条带。种群内多态性条带的百分比范围为58.22%至63.56%，在种群水平上平均为60%，在物种水平上为71.11%，表明小叶锦鸡儿物种具有相对较高的遗传变异。香农信息指数（I）和内氏基因多样性（h）呈现出相似的趋势。根据内氏基因多样性分析，种群间遗传变异的百分比为7.13% , 表明种群间遗传分化程度较低。种群间存在较强的基因流（Nm = 3.26）。虽然方差分析（AMOVA）也显示大部分变异存在于种群内（φ(ST)=4.1%），但在本研究中观察到种群间存在显著比例的变异（P<0.001），这表明在一定程度上种群间发生了遗传分化。基于曼特尔检验和先前研究的结果，小叶锦鸡儿的遗传结构模式在很大程度上符合距离隔离模型，然而，在小尺度上，种群间显著的遗传分化可能是由采样地点间的微环境差异而非地理因素增强的。对小叶锦鸡儿种群遗传变异的分析为锦鸡儿属物种的适应策略提供了有用信息。
