国产菱属植物亲缘关系的RAPD分析

Genetic relationship among Trapa species assessed by RAPD markers.

利用随机扩增多态性DNA(RAPD)技术对国产菱属(TrapaL.)植物10个种16个样品的遗传变异进行了研究.从50个10碱基随机引物中筛选出18个多态性引物用于正式扩增,共扩增出205条DNA带,其中多态性带为165条,占79.5%.根据DNA扩增结果计算了菱属各种间的Nei's遗传一致度和遗传距离,并采用UPGMA构建了聚类树状图.根据RAPD分析的聚类结果,结合野外观察和形态学性状的聚类分析我们建议:(1)将国产菱属植物划分为3个种,即欧菱(T.natansL.)、野菱(T.incisaSieb.etZucc.)和细果野菱(T.maximowicziiKorsh.);(2)除细果野菱外,其余2个种中果实角的数目均有从四角转变为二角的,所以把角刺数目作为菱属种间划分的主要依据这一点值得商榷;(3)欧菱、丘角菱可能是栽培菱的野生种或近缘种;(4)细果野菱为现存菱属中最原始的种.

To assess the genetic relationship between 10 species of genus Trapa, 16 samples were used for RAPD assay. 18 primers were screened from the 50 random primer,and a total of 205 DNA bands were amplified,among which 165(79.5%) were polymprphic. Based on the RAPD data, Nei's genetic identity and genetic diatance among the samples were calculated and a dendrogram was constructed by using UPGMA's method. According to the RAPD analysis combined with field observation and the cluster analysis of morphological characters, we suggest that Trapa plants in China can be classified into 3 species, namely T.natans L., T. incisa Sieb. et Zucc. and T. maximowiczii Korsh. The usual four-horn characteristic of the fruits in T.natans and T. incisa,but not in T. maximowiczii, can be changed under certain conditions so as to assume the shape of fruits with only two instead of four horns. Therefore, the reasonableness and reliability of taking the number of fruit horns as a criterion for discrimination between different species of Trapa are open to question. T.natans and T. japonicaare are most probably the wild or congener species from which the cultivated Trapa were evolved. The T. maximowiczii is believed to be the most original species of Trapa presently existing.