水杉自然居群遗传多样性的RAPD研究

RAPD Analysis of Genetic Diversity in the Natural Population of Metasequoia glyptostroboides, Central China

用随机扩增多态性方法对四川、湖南、湖北交界处的２７个水杉样本进行了基因组ＤＮＡ多态性分析．１１个随机引物共获得ＲＡＰＤ谱带１２１条，多态性谱带占５３％．聚类分析结果表明：水杉个体间的遗传距离与这些个体的地理分布相关，即相同产地个体间的遗传距离较小，不同产地个体间的遗传距离较大．与松柏目其它类群相比，水杉居群的遗传多样性程度高于银杉（３２％），而在所处的大类群中则处于中等水平．初步结果表明，尽管孑遗物种水杉的自然种群的目前分布范围和个体数目非常有限，但是它仍然保持着中度的遗传多样性水平．可推测。

Random amplified polymorphic DNA (RAPD) technique was used in analyzing population genetics of native Metasequoia glyptostroboides Hu et Cheng (Taxodiaceae), an endangered plant species, whose natural population today is distributed at the border area of Sichuan, Hunan and Hubei provinces in China Leaf samples were collected from 27 nature trees in their native population and 11 arbitrary primers were used to amplify 121 bands which contain 53% polymorphic RAPD loci The genetic distances among those 27 individuals are primarily related to their geographic distribution y comparing the percentages of polymorphic bands (PPB) of M glyptostroboides with those of 4 species in the Coniferales(32%～85%), it is shown that the genetic diversity of Metasequoia is higher than another endangered species of Cathaya argyrophylla (PPB=32%), and is moderately high among those plant species This result suggests that while an endangered species is represented by limited individuals in confined areas, the population may maintain a moderate genetic diversity Further studies using other genetic markers will be conducted to test this hypothesis