云南8个地区食蚊鱼种群的遗传结构分析

Genetic Structure of Gambusia affinis in 8 Regions of Yunnan

利用线粒体细胞色素b基因序列对云南8个不同地理种群食蚊鱼的遗传结构进行了分析,并对8个地理种群共计210个样本进行PCR扩增;采用分子方差分析方法,对种群的遗传变异进行分析。结果表明:获得了786 bp的基因片段序列,共检测到5个多态位点,定义了5种单倍型,其中单倍型H1由7个地理种群的156个样本共享(占样本总量74.3%),单倍型H2由7个地理种群的52个样本共享(占样本总量24.8%)。碱基频率含量(A+T)为53.2%,大于(G+C)46.8%。核苷酸多态性以东大河种群最高,其他7个群体较低。种群间的基因流较小为0.28。种群间遗传变异占总变异的52.74%,种群内的遗传变异占总变异的47.26%,种群间的变异是总变异的主要来源,云南地区的食蚊鱼种群整体较为稳定。

In this study, the genetic structure of Gambusia affinis which come from 8 different geographical populations in Yunnan was analyzed using mitochondrial cytochrome b technology. 786 bp sequences were obtained from 210 individuals of G.affinis, collected from 8 geographic populations in Yunnan Province. Of the 786bp sequences, 5 polymorphic sites defined 5 haplotypes. Among the haplotypes, the haplotype H1 was shared by 156 samples from 7 geographic populations （74.3% of the total length）, and the haplotype H2 was shared by 52 samples which come from 7 geographic populations （24.8% of the total length）. The base frequency content of G.affinis （A＋T） was 53.2%, which was greater than （G＋C） 46.8%. The nucleotide polymorphisms were the highest in the Dongdahe River population and the remaining 7 populations were lower. The gene flow between populations was 0.28. The results of molecular variance analysis （AMOVA） showed that 52.74% variation derived from different populations, 47.26% of the variation existed within the same population. The variation among the populations was the main source of total variation. The neutral analysis of the population of G.affinis showed that the population of G.affinis in Yunnan was relatively stable.