Study On Maternal Origin And Genetic Management Strategy In Captive Population Of Raccoon Dog

With the development and progress of aquaculture in China,how to prevent the loss of genetic diversity in captive population has become an important research topic.Raccoon dog is an important economic animal in China.Its maternal origin and genetic diversity are still unclear,which hinders the development of population genetic management.In this study,mitochondrial and microsatellite markers were used to study the maternal origin,genetic diversity and genetic structure of raccoon dog populations in Northeast and North China,and to calculate the offspring quality index.The main results are as follows.1.The mitochondrial cytochrome b(Cytb)gene and control region(CR)haplotypes of cultured raccoon dog population were limited,including 5 cytb genes and 6 CR haplotypes,among which 3 and 4 shared haplotypes with Russian subspecies of raccoon dog.The haplotype diversity was at a critical point(HD=0.50)and the nucleotide diversity was at a high level(PI>0.5%),but both of them were significantly lower than the wild Russian raccoon dog population.This pattern of genetic diversity may be due to the founder effect.In addition,the genetic diversity of reddish brown raccoon dog population was significantly lower than that of wild type and white type.Phylogenetic analysis showed that the domestic raccoon dog population was divided into three lineages,mainly Wusuli raccoon dog subspecies and closely related to the same subspecies of Russian wild population.One haplotype(ch5-dh5)shared the same haplotype lineage with the designated subspecies of raccoon dog from Vietnam.It is suggested that the name subspecies of raccoon dog from South China may be introduced by chance.2.A total of 11 microsatellite loci with high polymorphism(PIC>0.5)were selected.Among them,7 loci deviated significantly from H-W equilibrium(P<0.01),3 loci conformed to H-W equilibrium(P>0.05),and 1 locus deviated from H-W equilibrium(0.01<p<0.05).87 alleles were detected in raccoon dog population,with 6-9 alleles in a single locus.The average observed heterozygosity was 0.5984(0.2661-0.7984),and the average expected heterozygosity was 0.7128(0.5942-0.8312).The expected heterozygosity of all loci was higher than the observed heterozygosity.The average value of Shannon information index is 1.5077(1.2104-1.8449).This indicates that the raccoon dog population has high genetic diversity,but the distribution of alleles is uneven,genetic diversity is unstable,and inbreeding recession may occur.3.In this study,the quality index(OQI)of offspring was calculated according to the pairing scheme of all individuals in the population,which was composed of three indicators:heterozygosity,genotype diversity and allele.The results showed that the selection of breeding scheme with high offspring quality index could effectively increase the genetic diversity of population and prevent inbreeding decline.Meanwhile,the cumulative single parent exclusion rate of 11 microsatellite loci was 98.7%.The cumulative probability of exclusion was 99.999%.This indicated that the 11 microsatellite loci could be used to correct the recorded pedigree.Based on the estimated offspring quality index and corrected pedigree,more effective population genetic management can be carried out.