Genetic diversity analysis of Aristichthys nobilis populations from freshwater lakes in Jiangsu province based on mitochondrial DNA COⅠ gene
To understand the genetic status of Aristichthys nobilis populations from freshwater lakes in Jiangsu province of China,the genetic diversity and genetic structure of A.nobilis from six freshwater lakes(Tai Lake,Ge Lake,Changdang Lake,Gaoyou Lake,Hongze Lake and Luoma Lake)were analyzed based on COⅠ gene sequences.The results showed that in the analyzed 630 bp COⅠ gene fragment,the A+T base composition(55.3%)was higher than the G+C combination(44.7%).A total of 14 variable sites were detected and 9 haplotypes were defined from 223 COⅠ sequences.The haplotype diversity of the six populations ranged from 0.494 to 0.665,and nucleotide diversity varied 0.000 9 to 0.001 9.The total haplotype diversity(Hd)and nucleotide diversity(Pi)was 0.576 and 0.001 2,respectively,indicating high haplotype diversity and low nucleotide diversity pattern,demonstrating low genetic diversity.Analysis of molecular variance(AMOVA)showed that genetic variations mainly occurred within the populations(99.39%),the total genetic differentiation index(Fst)was 0.006 1.The pairwise Fst ranged from-0.022 8 to 0.044 5,and the genetic distance among populations varied from 0.001 2 to 0.002 7,indicating no significant genetic differentiation among populations.The haplotype neighbor-joining phylogenetic tree and network structure diagram both showed that the haplotypes were randomly distributed in six populations,without forming a specific geographic clade.Both neutral tests and mismatch distri-bution analysis indicate that A.nobilis had experienced significant population expansion.The study showed that the genetic diversity of A.nobilis populations from freshwater lakes in Jiangsu province was relatively low,and their genetic structure tended to be homogenized.So,more measures should be taken to improve the genetic diversity of A.nobilis.
万方数据
维普
