Study On Genetic Diversity Of Siniperca Kneri In The Yangtze River

Siniperca kneri(Sinipereinae:Serranidae:Perciformes)is an unique freshwater fish to East Asia.S.kneri is an important fish with high economic value.However,the natural and anthropogenic factors,such as overfishing,environment pollution,and dam building,which make the genetic diversity decrease quickly in the recent years.The main factors cause the decrease of genetic rescourses and block gene exchange among populations to some extent.This paper is based on the cytb and control region genes analysis the genetic diversity of S.kneri of four geographic population(CS-Chishuilee NJ-Nanjing,YC-Yichang,YY-Yueyang)along the Yangtze river water system.The study of the results are as follows:1.Study on genetic diversity of s.kneri populations:Cytb analysisThis study used PCR amplification and direct sequencing to obtain the Cytb sequences of a total of 79 individuals of four S.kneri populations of the Yangtze River(1141bp in length).Which found 26 distinct haplotypes.Haplotype diversity(Hd)ranged from 0.685(CS)to 0.924(YY)and nucleotide diversity(?)ranged from 0.00176(CS)to 0.00285(YC).The feature of high mean haplotype diversity(Hd)and the low mean nucleotide diversity(Pi)showed that S.kneri populations may have a bottleneck recently.Genetic distances ranged from 0.002 to 0.003 within or between populations.Pairwise Fst statistics suggested that highest level of differentiation was observed between CS and YY(Fst =0.12439),while lowest between NJ and YC(Fst ?-0.03254).Hierarchical analysis of molecular variance(AMOVA),the NJ,UPGMA and MP trees and median-joining(MJ)network analysis identified no significant phylogeographic structures.Tests of neutral evolution and mismatch distribution suggested that the whole S.kneri populations may have experienced a population expansion.Which appeared about 114,000 years ago.2.Study on genetic diversity of S.kneri populations:D-loop analysisThis study used PCR amplification and direct sequencing to obtain the D-loop sequences of a total of 79 individuals of four S.kneri populations of the Yangtze River(834-840bp in length).Which found 46 distinct haplotypes.Haplotype diversity(Hd)ranged from 0.754(CS)to 0.990(YY)and nucleotide diversity(?)ranged from 0.00548(CS)to 0.01412(YY).The genetic distances ranged from 0.005 to 0.014 within populations.The genetic distances of CS population(0.005)is the smallest and YY population(0.014)is the largest.The genetic distances ranged from 0.008 to 0.012 between populations.The distances between the YC population and other populations were greater.Pairwise Fst statistics suggested that highest level of differentiation was observed between CS and YY(Fst =0.08435),while lowest between NJ and YC(Fst =-0.00943).Hierarchical analysis of molecular variance(AMOVA),the NJ,UPGMA and MP trees and median-joining(MJ)network analysis identified no significant phylogeographic structures.Tests of neutral evolution suggested that the whole S.kneri population may have experienced a population expansion.