苦豆子等位酶遗传多样性研究

Allozyme Variation and Genetic Diversity of Sophora alopecuroides

目的探讨苦豆子不同种群的等位酶特性,从生化水平上分析其遗传变异。方法采用聚丙烯酰胺凝胶电泳技术,研究来源不同的24个苦豆子(Sophora alopecuroides L.)种群720个样本的遗传多样性,应用POPGEN 32分析数据,UPGMA绘制聚类图。结果 5个酶系统共检测到26个酶位点,多态位点百分数(P)为73.08%,平均期望杂合度(He)为0.337;Shannon信息指数(I)为0.517;各种群间基因分化系数(FST)为0.427;基因流(Nm)的平均值为0.687;种群间的遗传一致度为0.581 5～0.926 1,平均为0.769 0。聚类分析显示,种群间存在遗传分化。结论苦豆子具有较高的遗传多样性,种群间的遗传分化是其遗传多样性的主要来源;各种群间的遗传距离与地理距离间没有明显的关系。

OBJECTIVE To assess the allozymic variation and genetic diversity of Sophora alopecuroides populations at biochemical level. METHODS Vertical slab polyacrylamide gel electrophoresis was adopted to study the genetic difference of 720 samplesfrom 24 populations in Ningxia, Gansu, Qinghai, Xinjiang and Inner Mongolia. Data was analyzed by POPGEN 32, and a cluster diagram was presented by UPGMA. RESULTS A total of 26 loci in 5 enzyme systems （ esterase, EST ; malic enzyme, ME ; malate de-hydrogenase, MDH; peroxidase, PER; shikimate dehydrogenase, SKD） were detected and a high level of genetic diversity was revealed at population level. The percentage of polymorphic loci （P） was 73.08 % ; the mean expected heterozygosity （He） was 0. 337 ;Shannon＇s index （I） was 0. 517; the coefficient of gene differentiation （Fsr） among 24 populations was 0. 427, and the mean gene flow （Nm） was 0. 687, respectively. The genetic identity among the populations ranged from 0. 581 5 to 0. 926 1 with the average of0. 769 0. The genetic differentiation was found among the populations based on the clustering analysis. CONCLUSION There is a high level of genetic diversity among different populations, which mainly comes from genetic differentiation. No obvious relationship between the genetic distance and geographical distribution of the 24 populations is identified.