雄性榧树遗传多样性的SSR荧光标记分析

SSR analysis of genetic diversity of male Torreya grandis

【目的】旨在利用SSR荧光标记对榧树雄株5个野生居群的121个单株进行遗传多样性及群体遗传结构分析,为榧树雄株遗传背景、种质资源评价和优良种质筛选提供参考。【方法】采用CTAB法提取榧树基因组DNA,设计引物,通过荧光引物PCR扩增方法,利用毛细管电泳检测技术检测榧树雄株的多态位点。【结果】24对引物共检测到85个等位基因,变幅为2~7个,平均每个标记有3.542个,其中平均有效等位基因有1.915个。5个居群的平均Nei’s遗传多样性指数为0.365,平均Shannon’s信息指数为0.608。5个居群中,多态位点百分比为75.00%~95.83%,平均为82.50%,居群遗传多样性从大到小依次为嵊州居群、临安居群、富阳居群、黄山居群、淳安居群。居群间的基因流为4.172,遗传分化系数为0.096,遗传分化程度很低。聚类分析结果表明:5个居群的遗传相似度为0.865~0.978,平均为0.932。【结论】雄性榧树居群的遗传多样性较丰富。榧树雄株的遗传变异主要存在于居群内,但居群间也存在一定的基因交流。5个居群可以分为3大类群,这与表型的遗传多样性分析结果比较相似。

[Objective] This study aims to analyze the genetic diversity and population genetic structure of 121individual plants from 5 wild populations of male Torreya grandis using SSR fluorescent markers, in order to provide reference for genetic background, germplasm resource evaluation and elite germplasm screening of male T. grandis. [Method] The genomic DNA of T. grandis was extracted by CTAB method, and the primers were designed. The polymorphic sites of the male T. grandis were detected by capillary electrophoresis using fluorescent primer PCR amplification. [Result] A total of 85 alleles were detected by 24 pairs of primers,ranging from 2-7, with an average of 3.542 per marker, among which the average effective alleles were 1.915.The average Nei’s genetic diversity index and Shannon’s information index in 5 populations were 0.365 and 0.608 respectively. Among the 5 populations, the percentage of polymorphic sites ranged from 75.00% to 95.83%, with an average of 82.50%. The order of genetic diversity of the 5 populations from large to small was Shengzhou, Lin’an, Fuyang, Huangshan and Chun’an. The gene flow among the populations was 4.172, the coefficient of gene differentiation was 0.096, and the degree of genetic differentiation was very low. The results of clustering analysis showed that the genetic similarity coefficient(GS) of the 5 populations varied from 0.865 to 0.978, with an average of 0.932. [Conclusion] The genetic diversity of male T. grandis populations is relatively rich. The genetic variation of the male T. grandis mostly exists within the population, but the gene exchange is also present between the populations. The 5 populations can be divided into 3 groups, which is similar to the results of phenotypic genetic diversity analysis. [Ch, 4 fig. 6 tab. 32 ref.]