Analysis On Paternity And Genetic Diversity Of Mandarin Fish (Siniperca Chuatsi) Based On Microsatellite Markers

Siniperca chuatsi,commonly known as mandarin fish,osmanthus fish,belonging to Perciformes,Serranidae,Sinipercinae,Siniperca,it is a unique freshwater aquaculture fish in China.After the maturity of artificial propagation of Siniperca chuatsi,the artificial aquaculture of Siniperca chuatsi has been developing faster and faster,and it has become a higher quality species in freshwater aquaculture.In recent years,the ecological environment of Siniperca chuatsi has become worse,and the number of fish stocks has declined obviously,because of the deforestation of human beings,discharge of sewage from industry and agriculture and the overfishing of rivers.In the process of breeding,the inbreeding of Siniperca chuatsi has caused the degradation of the germplasm,weak resistance and the decrease of the growth rate,which have affected the development of the breeding industry of the Siniperca chuatsi seriously.In order to protect the germplasm resources,solve the inbreeding of Siniperca chuatsi,it is necessary to research the genetic diversity of the Siniperca chuatsi from the angle of molecular genetics.In this paper,20 microsatellite polymorphic primers were designed and screened.A full sib family of Siniperca chuatsi was established,and 10 microsatellite polymorphic primers were used to analyze paternity.The genetic diversity of six populations of Siniperca chuatsi was analyzed in Jiangsu province.In the paternity test,the parents were from Luoma Lake and Gaoyou Lake,One to one pairing,constructed 5 full sib families and took 10 tail offspring of each family,a total of 50 offspring,and selected 10 microsatellite markers to identify offspring and their parents.Genetic diversity parentage analysis was performed by popgene32 and Cervus software.The genetic diversity analysis showed that the average allele of the 10 microsatellite markers is 6.the average observed heterozygosity is 0.7733,the average expected heterozygosity is 0.8211,and the average polymorphism information content is 0.7875.By detecting the exclusion probability of microsatellite loci,when the parent genotype is unknown,the exclusion rate of single microsatellite locus(E-1P)is between 0.39-0.517,the average exclusion rate is 0.453,and the cumulative exclusion rate of 10 microsatellite loci is 0.997.When the genotype of a single parent is known.the exclusion rate of single microsatellite locus(E-2P)is between 0.57-0.686,the average exclusion rate is 0.633,and the cumulative exclusion rate is 0.999.The parental exclusion rate of a pair of parents is between 0.749-0.854,the average value is 0.805.The simulation results showed that the 10 microsatellite loci are suitable for 50 pairs of candidate parents in all cases and 100 pairs of candidate parents in the case of a pair of parents(sex known).When the parents are unknown,at least 7 microsatellite loci to reach more than 95%identification rate.At the time of paternity testing,50 tail offspring all find their own parents,the assignment rate is 100%.It showed that the 10 microsatellite loci can be applied to the paternity test of the Siniperca chuatsi.In the experiment of population genetic diversity,the genetic diversity of Siniperca chuatsi population was analyzed by collecting the 6 populations of Siniperca chuatsi in Jiangsu province.The genetic diversity of 6 populations of Siniperca chuatsi was analyzed with 20 microsatellite markers.A total of 842 alleles were obtained in 20 microsatellite loci,every locus has 5-9 alleles,and 6 populations of Siniperca chuatsi are polymorphic at every locus.The average effective allele of Siniperca chuatsi population in the Yangtze River is 6.5248,the average expected heterozygosity is 0.922 and the average polymorphic information content is 0.8273.It is the highest in the six populations of Siniperca chuatsi.On the contrary,the average effective allele of the population of Siniperca chuatsi in Taihu Lake is 4.8623,the average expected heterozygosity is 0.8369,and the average polymorphism information content is 0.7619.It is the lowest in the six populations of Siniperca chuatsi.G-Statistical analysis of microsatellite loci in Siniperca chuatsi revealed that there is a slight inbreeding phenomenon among populations of Siniperca chuatsi.The genetic distance and genetic similarity between the population of Siniperca chuatsi showed that the genetic differentiation is the lowest between the population of Siniperca chuatsi in Taihu Lake and Gehu Lake,and the relationship is closest;the genetic differentiation is the highest between the population of Siniperca chuatsi in Taihu Lake and Luoma Lake,and the relationship is farthest.The UPGMA cluster analysis showed that the population of Siniperca chuatsi in Gaoyou Lake and Hongze Lake are clustered into one group.and the population of Siniperca chuatsi in Taihu lake and Gehu lake are clustered into one group.In this study,the result of paternity test of Siniperca chuatsi and the genetic diversity analysis of the Siniperca chuatsi population in Jiangsu province laid a foundation for the construction of genetic map.It provided a theoretical basis and technical means for family breeding and the protection of the germplasm resources of Siniperca chuatsi in Jiangsu province.