中国胭脂鱼线粒体控制区遗传多样性分析

Genetic Diversity Analysis of Mitochondrial D-loop Region of Chinese Sucker ( Myxocyprinus asiaticus )

利用PCR技术扩增了采自长江宜昌江段和清江的 8尾中国胭脂鱼线粒体DNA控制区全序列。研究发现该种具有脊椎动物线粒体控制区的一般结构 .在获得的 95 8bp的碱基序列中 ,共检测出 32个多态性核苷酸变异位点 ,多态位点比例为 0 .0 33。核苷酸的变异位点除一个为缺失外 ,其余全部为碱基转换 .变异位点主要集中在 5 5～36 5bp高变异区 ,而其他区域突变稀少。个体的变异在 0～ 1.36 %之间 ,表现出较大的个体多态性差异。中国胭脂鱼的线粒体控制区的变异远大于美国胭脂鱼 (Moxostomarobustum)的 0 .0 16。

Chinese sucker, Myxocyprinus asiaticus, is an endemic species of China and also the only representatives of family Catostomidae in Asia. The fish was naturally distributed in Yangtze River and Mingjiang River and now few could be captured because of pollution and overexploitation. The fish has been listed in the second class of preserved animal in China. Studying and assessing its population structure is an imperative and fundamental work for making effective protection strategies. We amplified and sequenced the D loop region of mtDNA of 8 samples. The size of the D loop region is about 958bp. A total of 32 variation loci were detected and the mutation rate was 0.033. All the mutation came from nucleotide substitution except one nucleotide deletion. Most of the nucleotide variations were found between the 55～365bp region. The individual mutation rate varied from 0～1.36%,which exhibited nucleotide polymorphism to some extent among 8 samples. Compared with RAPD and other PCR based methods,the directily sequencing of mtDNA D loop region revealed much more genetic diversity. Meanwhile,the D loop region of Moxostoma robustum derived from GenBank was aligned with that of Chinese sucker through CLUSTAL software. By comparison,we found that the mutation rate (0.033) of D loop of Chinese sucker is higher than that of Moxostoma robustum (0.016).