Genetic Diversity Of Siniperca Scherzeri Populationin Miaoling Mountain

In order to understand the current status of the germplasm resources of Siniperca scherzeri in the Miaoling Mountains,this study is based on morphological methods,mitochondrial DNA Cytb and COI genes,and nuclear DNA ITS-1 gene marker technology.The genetic structure and genetic diversity of wild Siniperca scherzeri populations in 3 water systems and 7 rivers in the Sinan section of the Wujiang River system and Zhangjiang River,Songtao River,Jinjiang River,Wuyang River and Qingshui River in the Yuanjiang River system in the north were studied.The research results are as follows:1.Based on the combination of traditional morphological traits data and frame structure data,the morphological differences of Siniperca scherzeri populations in three water systems in Miaoling mountainous area were compared and studied using multivariate analysis methods.The results showed that there were significant differences in nine countable traits including dorsal fin spines,dorsal fin rays,pectoral fin rays,pelvic fin rays,anal fin rays,caudal fin rays,pyloric lobes,lateral line scales,and first gill rakers outside the first branchial arch(P<0.05);The first six principal components are extracted from the principal components,and their cumulative contribution rate is 72.668%.The first three principal components contribute significantly to the difference in appearance between groups,mainly due to the length of the caudal stalk,the distance between the eyes and the body width.The influence of traits;the stepwise discriminant method was used to establish the characteristic discriminant function of the three groups,and the accuracy rate of the interactive verification discrimination was 81.5%;the morphological cluster map results showed that the morphological relationship between Yuanjiang and Liujiang groups was firstly clustered into one group.Then gather with the Wujiang population;the difference in tail stalk length/body length traits between the Wujiang population and the Yuanjiang and Liujiang populations reaches the subspecies level(variance coefficient>1.28).In summary,there are certain differences in morphology among the three groups of Siniperca scherzeri in the Miaoling Mountains.Among them,the Liujiang River and Yuanjiang River have relatively small morphological differences,and the Wujiang River and the Wujiang River are more different.The established discriminant equation can distinguish the three groups.2.Based on the genetic analysis of the mitochondrial DNA Cytbgene,the results showed that the average content of bases A,T,C,and G in the population of Siniperca scherzeri in the Miaoling mountain area were 24.3%,27.3%,32.9% and 15.5% respectively;365 pieces of 1141 bp length In theCytb gene sequence,there are 28 polymorphic sites,29 haplotypes are defined,and each population has a shared advantage hap6;the population is divided into 2 pedigrees,Clade 1 is widely distributed in 3 water systems and 7 rivers,and Clade 2 Limited to 2 water systems and 5 rivers in the north of Miaoling;the northern population shows high haplotype diversity and low nucleotide diversity,while the southern one has low haplotype diversity and low nucleotide diversity;the genetic variation of Siniperca scherzeri Firstly,it comes from individuals within the population,and secondly is the isolation between water systems or watersheds;there is a high degree of genetic differentiation between the north and south populations;the two lineages have experienced population expansion events in the late Pleistocene.Comprehensive analysis revealed that the Miaoling Siniperca scherzeri population has a common maternal ancestor,and the genetic diversity is high in the north and low in the south,and there is a significant genetic differentiation between the northern and southern populations.3.The results of genetic analysis based on the mitochondrial DNA COI gene: The content of bases A,T,C and G in the Siniperca scherzeri population are 25.1%,28.6%,28.2% and 18.2%,respectively.The 1560 bp homologous sequence encodes a total of 503 There are 34 polymorphic sites in 365 sequences,and 34 haplotypes are defined.hap1 is a dominant haplotype shared by all water systems or river populations;this gene region fails to establish an obvious systematic lineage relationship;heredity Diversity is also the high haplotype diversity and low nucleotide diversity in the northern populations,while the low haplotype diversity and low nucleotide diversity in the south.The genetic variation mainly comes from within the population;the genetic differences between populations are relatively high.Small,there is also a high degree of genetic differentiation between the north and south populations;3 water system groups have recently experienced expansion events.The analysis indicated that the Miaoling Siniperca scherzeri based on the mitochondrial COI gene has no obvious phylogenetic relationship and belongs to the same matrilineal ancestor group.The haplotype genetic diversity is rich,but the nucleotide diversity is low.There is genetic diversity between the northern and southern geographic populations.Differences and significant genetic differentiation.4.Results of genetic diversity analysis based on rDNA ITS-1 sequence: The average content of bases A,T,C and G in the population is 20.4%,8.7%,33.2% and 37.7%,of which C+G(70.9%)Is significantly higher than A+T(29.1%);the sequence length of ITS-1 is between 718-734 bp,there are 8 length sequence types,365 sequences have 16 polymorphic sites,and a total of 22 haplotypes are defined Hap1 is an ancestral haplotype shared by all river systems,and the other 21 haplotypes are derived from it,representing 343 individuals of the Miaoling Siniperca scherzeri population;the population shows low haplotype diversity and low nucleosides Acid diversity;genetic distance,genetic differentiation coefficient and gene flow all show that there is no genetic differentiation among populations.rDNA ITS-1 gene analysis suggests that Miaoling Siniperca scherzeri belongs to the same population,with low haplotype diversity and poor genetic diversity.In summary,although the Siniperca scherzeri populations in the Miaoling mountainous area belong to different watersheds and water systems,there is no obvious geographical distribution pattern in terms of phylogenetic relationship,and they belong to the same ancestral genetic source.Extranuclear mitochondrial DNACytb gene and COI gene are rich in genetic diversity,while nuclear DNA ITS-1 is poor in genetic diversity.Dueto different environments,geographical barriers and evolutionary differences,certain morphological and genetic differences have occurred between groups.