Construction Of Molecular Pedigree And Analysis Of Genetic Structure Of Large Tailed Han Sheep Population

Pedigree record can clarify the breeding relationship among individuals.It is a kind of modern breeding practice that focuses on individual selection and also an important source of information for animal genetic breeding.Nowadays,with the development of social economy,people overly pursue the high yield and introduce a large number of exotic breeds,which has caused the great damage to Large Tailed Han Sheep and the amount of livestock.At present,it is imminent to establish a Large Tailed Han Sheep population in Shandong Province.Due to the complex origins of the Large Tailed Han Sheep and the loose management of the original protected breeding,the problems are that Molecular pedigree and the genetic structure are unclear.To protect the resources of the Large Tailed Han Sheep,we need make it clear through a molecular way to know about the parent-child relationship,build molecular pedigrees,identify hybrid individuals,and formulate breeding plans.In this study,145 individuals of the Large Tailed Han Sheep are used as materials,40 of which are selected for pool testing through 25 microsatellite loci.15 microsatellite loci with high polymorphism are screened for parental rights to identify and build molecular pedigrees.Cervus 3.0 analyzes the parent-child relationship,such as: number of alleles(N),single-site unknown parental genotype exclusion probability(NE-1P),known parental genotype exclusion probability(NE-2P),cumulative exclusion probability at multiple loci(CEP),and Hardy-Weinberg equilibrium test.Pedigraph 3.0 can be used to draw pedigrees with complex inbred line structures.SPSS can be used to analyze the known parent exclusion probability and unknown exclusion probability and PIC,He,Ho,K,N polymorphism of each microsatellite locus.Genepop,SPAGeDi,Arlequin,SPSS,and MEGA can be used to analyze the genetic structure of the constructed molecular pedigree.The results show that:(1).Among the 40 Large Tailed Han Sheep tested in mixed pools,polymorphisms are screened at 25 loci.By comparing and analyzing the number of alleles and polymorphic information content,15 alleles are selected,which are tested there are 293 alleles and the alleles are above 13,and the average allele was 19.533.In what is mentioned above,INRA063 is in the Large Tailed Han Sheep and the number of alleles reach up to 30.And the number of BM1225 and MB023 alleles are relatively small: there are 13.The PIC of all the loci are in the range of 0.707-0.895,which all exceed 0.5 and belong to highly polymorphic loci.The average expected heterozygosity of the Large Tailed Han Sheep population is higher to 0.8376.The selected 15 microsatellite loci can be used for paternity analysis of Large Tailed Han Sheep.(2).When both parents are unknown,the cumulative paternal non-exclusion probability is 0.99999028,and the credibility is above 80%.Finally,from the 145 samples,16 of which have found the father and 11 have found the mother.The kinship coefficients used to infer the distant and close relationship.According to SPAGeDi,the parent-child relationship and kinship coefficient clustering results,it is divided into 10 families.Pedigraph 3.0 is used to construct 10 families Molecular pedigree and Pedigree of Population Molecules.(3).In the large tail Han sheep population,the genetic distance between POP8 and other populations is relatively high,which is greater than 0.1;except for the genetic distance between POP8 and other families,the genetic distance between POP4 and POP7 is greater than 0.1,and the genetic distance between other populations is less than 0.1.However,the polymorphic information content(PIC)is greater than or equal to 0.5,which indicates that the genetic variation within the family is high.Through genetic distance and inbreeding coefficient,it can be inferred that there is inbreeding in the family.The presence of inbreeding and the small genetic distance are consistent with the fact that there is no genealogical records of the original breeding of the Large Tailed Han Sheep population and the random mating.To sum up,the 15 microsatellite loci selected were highly polymorphic in thepopulation of big-tailed cold sheep.According to the result of the relationship analysis and the coefficient of relationship,we can divide 10 families and construct family genealogy.There was a certain genetic distance between all the families,the genetic variation was higher in the family of big tail cold sheep,and there was inbreeding in the family.