七筋菇自然居群的遗传结构分析

采用ISSR分子标记,对七筋菇(Clintonia udensis)17个居群的遗传多样性与遗传结构进行了研究。结果表明:七筋菇不同居群的多态位点百分率PPB为11.90%~59.52%,总的多态位点百分率PPB为98.8%,具有高的遗传多样性。Shannon多样性指数(0.6903)和基因分化系数(GST=0.6944)均揭示出七筋菇居群间存在明显的遗传差异,AMOVA分析结果也显示遗传变异主要发生在居群之间(81.47%),而居群内部的遗传变异仅为18.53%。七筋菇居群间的遗传距离从0.1871~0.6632,平均为0.3838,大于同一物种居群间的平均遗传距离值(0.05),同样表明七筋菇居群间的遗传多样性存在较大差异。七筋菇居群间的基因流Nm=0.2200,远远低于一般广布种植物的基因流(Nm=1.881)。Mantel检测显示居群间的遗传距离与地理距离之间没有显著相关性(r=0.029,P=0.3196)。七筋菇分布范围广以及其进化历史是其具有高遗传多样性的原因;居群间存在较高遗传变异可能是由于七筋菇本身的生物学特性、有限的基因流以及遗传漂变等原因造成的。

Population Structure of Clintonia udensis (Liliaceae) in China

In this study,15 ISSR primers were used to reveal the genetic diversity and genetic structure of 17 Clintonia udensis populations.The results showed that a relatively high genetic diversity existed in C.udensis,with the percentage of polymorphic bands(PPB)from 11.90% to 59.52% at population level ranged,and 98.8% at species level.Moreover,a high level of genetic differentiation among populations was detected based on Shannon's information index(0.6903),gene differentiation index GST(0.6944),and AMOVA analysis(81.47%)(P<0.003).The variation of genetic distances among populations ranged from 0.1871 to 0.6632(with an average of 0.3838),which was higher than that among intraspecies populations(0.05).The gene flow among populations(Nm=0.2200)was much lower than that of the widespread species(Nm=1.881).In addition,there was no significant correlation between genetic distance and geographical distance among the population studied(r=0.029,P=0.3196).The biological characteristics of this species,limited gene flow and genetic drift might account for the existence of relatively high inter-populational genetic variation.The high level of genetic diversity was probably related with its wide geographical distribution and its evolutionary history.