大花黄牡丹遗传多样性的SRAP分析

应用SRAP标记对西藏特有植物大花黄牡丹的遗传多样性进行研究。用16对引物从5个自然居群79个单株中共检测到396个有效位点,其中多态性位点357个。在物种水平上,多态位点百分率(Ppl)为90.15%,Shannon表型多样性指数(Ηsp)平均为0.2521;居群水平上的Ppl为31.82%,Shannon表型多样性指数(Ho)为0.0694～0.3428,平均值(Ηpop)为0.1307。上述遗传参数表明,大花黄牡丹具有丰富的物种遗传多样性,5个居群中自然居群C的遗传多样性最高(Ppl=82.32%,Ho=0.3428)。据AMOVA分析结果,总的变异中有41.58%的变异存在于居群间,58.42%的变异存在于居群内,居群分化较显著(ΦST=0.4158,P<0.001),由POPGENE1.32得到的居群间遗传分化系数GST(0.4309)和Shannon表型多样性指数计算的居群间遗传多样性所占比例(0.4816)也表明了类似的遗传结构。Mantel检测表明地理距离和Nei’s遗传距离间相关不显著(P>0.05)。利用NTSYSPC(2.1)软件构建大花黄牡丹5个居群79个个体的UPGMA聚类图,遗传相似系数变幅在0.47～0.99,大多数居群内的个体表现出较为密切的亲缘关系(如居群B,D,E),但也有一些居群的个体未聚在一起(如居群C)。依据大花黄牡丹居群遗传变异特点,初步探讨其保护和利用策略。

SRAP Analysis of Genetic Diversity of Paeonia ludlowii in Tibet

Sequence Related Amplified Polymorphism (SRAP) analysis was applied to study the genetic diversity of Paeonia ludlowii, a species only distributed in Tibet of China. Sixteen pairs of SRAP primers were used to evaluate the genetic diversity of 79 samples from five natural populations. A total of 396 valid loci were obtained, of which 357 were exhibited polymorphism. The percentage of polymorphic loci (Ppl) and the mean diversity estimated with Shannon’s index of phenotypic diversity(Ηsp) at species level were 90.15% and 0.252 1, respectively.At population level, Ppl was 31.82% and Shannons index (Ho) ranged from 0.069 4 to 0.342 8, with an average value(Ηpop) of 0.130 7. Among the five populations, population C was especially more diverse(Ppl=82.32%,Ho=0.342 8). Those results indicated that there was a relatively high level of intraspecific genetic diversity. Analysis of molecular variance(AMOVA) demonstrated that a high degree of genetic differentiation occurred among the populations (ΦST =0.415 8,P<0.001). The proportion of genetic variation among populations was 41.58%, while the proportion within population was 58.42%. A similar analysis result was exhibited by the genetic differential index(GST) of 0.430 9 and the proportion of diversity among populations with Shannons index (Hsp-Hpop)/Hsp]of 0.481 6. Mantel test showed that there was no significant correlation between geographical distance and genetic distance (r=0.597 5,P=0.905 5) among populations. A dendrogram conducted by UPGMA method using NTSYSPC(2.1) demonstrated that the range of genetic similarity coefficient was 0.47-0.99. The most of the individuals came from the same population had close genetic relationship, such as population of B, D, E,but individuals from population C could not be clustered together completely. A strategy for the conservation and utilization of P. ludlowii based on genetic diversity was proposed.