长江中下游5个湖泊黄颡鱼(Pelteobagrus fulvidraco)种群线粒体细胞色素b基因的遗传变异分析

Genetic variation analysis of yellow catfish(Pelteobagrus fulvidraco) from five lakes in the middle and lower reaches of the Yangtze River based on Mitochondrial DNA cyt b

对长江中下游5个湖泊的黄颡鱼种群的线粒体DNA细胞色素b基因进行了PCR扩增、测序,获得了955 bp的序列.分析显示,cyt b序列中A+T含量略高于G+C含量,共检测到54个变异位点,60个样本得到37个单倍型,平均单倍型多样性为0.945±0.018,核苷酸多样性为0.00419±0.00043,遗传多样性表现中等.太湖种群与滆湖种群间的遗传距离最远为0.00651,鄱阳湖种群和巢湖种群之间遗传距离最近为0.00375.分子方差分析(AMOVA)表明,群体间遗传分化系数Fst为0.0684,几乎所有变异都来自群体内,群体间遗传分化极小.cyt b序列构建UPGMA系统进化树显示,5个种群没有分化成不同的分枝谱系,种群间存在广泛的基因交流.

The mtDNA cyt b gene of yellow catfish from five lakes in the middle and lower reaches of the Yangtze River was ampli- fied and sequenced. Result showed that the average contents of A ＋ T were a little higher than that of G ＋ C in the aligned se- quences of 955 bp. 54 variable sites were detected and 37 haplotypes were recovered. The haplotype diversity and nucleotide diver- sity were 0. 945 ±0. 018 and 0. 00419 ±0. 00043, respectively. The genetic distance between Lake Taihu population and Lake Ge- hu population displayed the highest, up to 0. 00651, while that between Lake Poyang and Lake Chaohu was the lowest to 0. 00375. The fixation indices （ Fs1 ） of analysis of molecular variance （AMOVA） among populations was 0. 0684, illustrating no significant population structure. The phylogenetic tree of cyt b built with MEGA 4.1 showed that five populations were not clustered into clades based on genetic distance. There was extensive general flow between yellow catfish populations from five lakes in the middle and lower reaches of the Yangtze River.