云南尼泊尔桤木遗传多样性研究

分别在云南省来凤山、高黎贡山、鸡足山、苍山和无量山，采集58个尼泊尔桤木Alnus nepalensis叶样品，提取总DNA，对它们进行RAPD—PCR分析。3个随机引物其扫描到DNA位点85个，其中多态性位点64个，样品内的多态性为75．30％；用非加权组法（UPGMA）聚类分析，建立尼泊尔桤木分子聚类树状图，以相似系数0．68为标准分为6类；用POPGENE软件分析Nei’s遗传多样性指数和Shannon遗传多样性指数。结果表明：云南尼泊尔桤木遗传多样性丰富，其中，鸡足山尼泊尔桤木居群多样性指数最高，无量山居群中，分布在南坡的尼泊尔桤木多样性指数高于分布于北坡的样品。尼泊尔桤木的分布及遗传结构与环境区域有密切的关系，区域特点是决定尼泊尔桤木遗传多样性水平的重要因子之一。该结果对于研究尼泊尔桤木遗传多样性以及它与共生固氮弗兰克氏菌Frankia的协同进化有一定的利用价值。图2表2参25

Genetic diversity of Alnus nepalensis in Yunnan revealed by RAPD-PCR

Alnus nepalensis is the oldest species of Betulaceae, mainly distributed in Yunnan Province, which can fix nitrogen. The objective is to study its genetic diversity and assess its resources. In Yunnan Province 58 naturally occurring samples of A. nepalensis were collected from Laifeng, Gaoligong, Jizu, Cang, and Wuliang Mountains. The genomic DNA of A. nepalensis was as extracted by the cetyltrimethylammonium bromide （CTAB） method, and their DNA polymorphism was analyzed by random amplification of polymorphic DNA （RAPD）-polymerase chain reaction （PCR） with 3 optimum primers. A total of 85 DNA bands were amplified, and a DNA molecular UPGMA （ unweighted pair group method using arithmetic averages ） dendrogram was established. Also, for the samples, Nei＇ s gene diversity and Shannon＇ s information index were computed by POPGENE software Numerical Taxonomy SYStem （NTSYS） software. Results indicated that 64 of the 85 DNA bands （75.3%） were polymorphic, and with the dendrogram A. nepalensis samples were placed into 6 groups with a standard similarity coefficient of 0. 68. A. nepalensis possessed abundant genetic diversity with the highest diversity found in the Jizu Mountains. In the Wuliang Mountains genetic diversity of A. nepalensis was richer along the southern slope than the northern. Also, a close relationship between the genetic structure of A. nepalensis and the environment was shown with genetic diversity. Ch, 2 fig. 2 tab. 25 ref. ]