锥栗自然居群遗传多样性的ISSR分析

ISSR Analysis of Genetic Diversity in Natural Populations of Castanea henryi

采用20条ISSR分子标记对栗属中国特有种-锥栗(Castanea henryi)的16个自然居群进行了遗传多样性与遗传关系分析。在449份试材上共扩增得到379个位点,其中多态性位点378个,多态性位点百分率(PPL)达99.74%,平均期望杂合度(He)为0.2950,Shannon信息指数(I)为0.4522;居群水平遗传多样性为46.09%,且不同居群遗传多样性水平有较大差异,16个自然居群中以湘西居群的遗传多样性水平最高(PPL=53.30%,He=0.1861,I=0.2781),其次为靖州、庆元、昭通及都江堰居群,南平居群最低(PPL=36.94%,He=0.1202,I=0.1817)。Nei's遗传多样性和AMOVA分析表明,居群间产生了较大的遗传分化(Gst=0.4466),锥栗自然居群内的遗传变异稍占优势(52.51%)。UPGMA聚类分析将16个锥栗居群分为2大类5亚类。湘西地区可能是锥栗的次生分布中心和现代遗传多样性分布中心,是锥栗研究的资源中心,也是最有价值的基因库,需要重点保护。

Genetic diversity and genetic relationships of 16 natural populations of Castanea henryi.were assessed by ISSR.379 loci were identified in 449 individuals,of which 378 loci were polymorphic,the polymorphic loci percent（PPL） was 99.74%.The mean expected heterozygosity（He） and the Shannon information index（I） was 0.2950 and 0.4522,respectively.In population level,the PPL was 46.09%.The genetic diversity in different population was not consistent.Compared with those from other 15 regions,Xiangxi region had the higher level of diversity（PPL =53.30%,He = 0.1861,I = 0.2781）.A high level of genetic differentiation was detected among populations based on analysis of Nei’s genetic diversity and molecular variance（AMOVA）,Which showed that a large genetic differentiation existed among populations（Gst = 0.4466）,and distribution of genetic variation within and among populations was 52.51% and 47.49%,respectively.16 populations were clustered into 2 groups and 5 subgroups by the UPGMA analysis.Xiangxi region might the secondary distribution center and modern center of genetic diversity of C.henryi,also was the resource center.It was the most valuable gene pool,therefore,natural populations of C.henryi in this region need deserve prior conservation.