黑脊倒刺鲃线粒体DNA多样性分析

Mitochondrial DNA Diversity of Spinibarbus caldwelli

黑脊倒刺鲃(Spinibarbus caldwelli)是分布于中国南方各水系,具有重要经济价值鱼类。文中对来自赣江、九龙江、漓江等3水系的瑞金、长泰、桂林等3个黑脊倒刺种群共61个样品的线粒体DNA细胞色素b基因(mtDNA cyt b)进行PCR扩增和测序,对序列进行分析。结果发现,在全长(1 141 bp)cyt b共检测到45个变异位点,61个样品分属16个单倍型,与其它鲤科鱼类比较,黑脊倒刺鲃的遗传多样性水平比较低。分子方差分析(AMOVA)及系统发育分析显示,瑞金和长泰种群没有显著遗传差异,而它们与桂林种群存在显著遗传分化,提示黑脊倒刺可能存在多个地理种群。

The barbel fish, Spinibarbus caldwelli, distributing widely in rivers in the south of China, is a species of economic importance.. Knowledge on its genetics is limited. In this paper, 61 specimens of S. caldwelli from Ruijin（the Ganjiang River, Jiangxi Province; n=19）, Changtai （the Jiulongjiang River, Fujian Province; n=22） and Guilin（the Lijiang River, Guangxi Province; n=20） were used to test the genetic diversity and structure. The mitochondrial cytochrome b gene（cyt b） were amplified by means of PCR and sequenced. Analysis of the sequence set disclosed 45 variable nucleotide sites among the complete gene and 16 haplotypes from all specimens. The haplotype diversities（л） were 0. 008 13, 0. 012 16 and 0. 001 88 respectively, and the nucleotide diversities（ h ） were 0. 649, 0. 693 and 0. 863 respectively. The genetic diversity was low compared with other cyprinids. Analysis of moleculer variance（AMOVA） and phylogenetic relationships of hapIotypes showed that no genetic divergence occurred between Ruijin and Changtai populations, and dramatic divergence（FST 〉0.22） occurred between the two populations and Guilin population. The results indicated that more distinct populations of S. caldwelli may exist in other rivers.