孑遗植物桫椤种群遗传变异的RAPD分析  

RAPD analysis of the genetic variation within populations of a relict tree fern,Alsophila spinulosa (Cyatheaceae)

作　　者：王艇[1] 苏应娟[1] 李雪雁[1] 郑博[1] 陈国培[1] 王伯荪[1] 

机构地区：[1]中山大学生命科学学院,广州510275

出　　处：《生态学报》2003年第6期1200-1205,共6页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目 (3 0 1 70 1 0 1);国家自然科学基金重点资助项目(3 983 0 3 1 0);广东省自然科学基金资助项目(0 1 1 1 2 5 )~~

摘　　要：应用 RAPD标记分析了桫椤分布在海南尖峰岭及霸王岭 ,广东塘朗山、黑石顶及大西山孑遗种群的遗传变异。 2 8个引物共检测到 1 1 8个位点 ,其中多态位点 33个 ,多态位点比率 2 7.97%。Shannon多样性、Nei遗传分化和分子方差分析 ( AMOVA)结果一致显示尖峰岭种群遗传多样性最大 ,霸王岭种群次之、塘郎山种群第三 ,黑石顶种群第四 ,而大西山种群最小。种群的遗传变异主要发生在种群间 ;Shannon指数测出的种群间遗传多样性所占比率为 79.1 0 % (基于表型频率 )和 77.85 % (基于基因频率 ) ,Nei基因分化系数 ( Gst)达 80 .69% ,分子方差分析也表明种群分化极为显著 ( Φst=0 .82 86,P<0 .0 0 1 )。桫椤的种内遗传多样性水平很低 ,种内 Shannon多样性仅为 0 .0 641 (基于表型频率 )和 0 .1 1 2 4 (基于基因频率 ) ,总基因多样性只有 0 .0 770。另外 ,Jaccard相似性系数的 UPGMA分析结果显示 5个种群分为两个分支 :尖峰岭种群和霸王岭种群组成一分支 ;黑石顶、塘郎山和大西山种群组成另一分支 ,并且三者中前两者的遗传关系更为密切。聚类分析结果还得到主成分分析的支持。根据桫椤种群的遗传变异特点 ,初步探讨了保护策略。RAPD markers were used to assess genetic variation within and among relict populations of the tree fern Alsophila spinulosa (Cyatheaceae) from Jian Feng Ling (JFL) and Ba Wang Ling (BWL) in Hainan Province,as well as Tang Lang Shan (TLS),Hei Shi Ding (HSD) and Da Xi Shan (DXS) in Guangdong Province of southern China.Twenty\|eight random primers detected 118 sites of which 33 (27 9%) were polymorphic.Calculations of Shannon diversity,Nei genetic differentiation,and AMOVA all consistently indicate that the JFL population possesses the greatest genetic diversity,followed in order by the BWL,TLS,HSD,and DXS populations.The genetic variation was found to be partitioned mainly among rather than within populations.Percentages of genetic diversity among populations as determined by Shannon index were 79 10% and 77 85% based on phenotype and gene frequencies,respectively.Nei's gene diversity coefficient (G\-\{ST\} ) was 80 69%.AMOVA also demonstrated that these relict populations are highly differentiated ( Φ\-\{st\} =0 8286, P <0 001).Overall,very low levels of genetic diversity were detected within A.spinulosa. Shannon diversity within the species was 0 0641 from phenotype frequencies and 0 1124 from gene frequencies,whereas the corresponding total Nei gene diversity was 0 0770.UPGMA analysis based on Jaccard similarity coefficients showed that these five populations cluster into two groups:the JFL and BWL populations together,and the HSD,TLS,and DXS populations in a second cluster.The UPGMA results were also supported by a principle components analysis (PCA) of RAPD phenotypic data.A strategy for the conservation of A.spinulosa based on genetic diversity is proposed.

关 键 词：桫椤 种群遗传 RAPD标记 遗传变异 孑遗植物 

分 类 号：Q943[生物学—植物学]