用RAPD技术对特化等级裂腹鱼类亲缘关系的探讨

为确定特化等级裂腹鱼类的遗传分化关系 ,对 7种 2 2个裂腹鱼个体进行随机扩增多态DNA(RAPD)研究。从所使用的 40个随机引物中 ,选择了 37个扩增带谱清晰的引物进行分析。根据构建的分子系统树显示 ,特化等级裂腹鱼类划分为 3个属级分类单元较为合适 ,这与采用形态学特征进行系统分析所得出的结论一致。在 2 2个个体之间遗传距离矩阵中 ,最大的遗传距离指数达到了 90 38% ,此外 ,还有较多的遗传距离指数也在 6 0 %～ 90 %之间。通过分析 ,认为用RAPD标记技术来分析属级或属级以上分类单元的亲缘关系 ,具有一定的适用性。对于一些遗传差异较大的类群 (如裂腹鱼类 ) ,应用属级或属级以上分类单元的亲缘关系 ,很可能会出现个体之间遗传距离接近或达到 10 0 %的情况 ,从而无法探讨其相互之间的亲缘关系。

GENETIC RELATIONSHIPS OF THE SPECIALIZED SCHIZOTHORACINE FISHES INFERRED FROM RANDOM AMPLIFIED POLYMORPHIC DNA ANALYSIS

The specialized schizothoracine fishes belong to subfamily Schizothoracinae (Cyprinidae).Compared to other fishes in the same subfamily,the specialized schizothoracine fishes have the following characters:only 1 pair of barbels,2 rows of pharyngeal teeth,scales degenerated,and even degenerated entirely in genus Gymnodiptychus (Cao et al .,1981).There are 9 species and subspecies belonging to 3 genera Diptychus (Steindachner,1866), Ptychobarbus (Steindachner,1866) and Gymnodiptychus (Herzenstein,1892)] in this group.In this paper,random amplified polymorphic DNAs (RAPDs) were used to investigate genetic relationships among 22 individuals of the fishes,which represent 6 species and 4 genera,Schizothorax,Diptychus,Ptychobarbus and Gymnodiptychus respectively.234 RAPD markers were observed by using 37 arbitrary primers (10?bp).The molecular phylogenetic tree constructed by NJ (Neighborjoining) method indicated that these 22 individuals could be divided into 6 clusters (each cluster represents one species).Upon the relationships among the 3 genera,Diptychus,Ptychobarbus and Gymnodiptychus,the conclusion was the same as that concluded from the phylogenetic analysis by using morphological characters.The result showed that RAPD could be used to study the phylogenetic relationships of closely related genera.