Construction Of Molecular Genealogy And Analysis Of Family Genetic Characteristics In Two Goat Breeds

In breeding practice, pedigree errors will result in inbreeding, germplasm degradation and loss of genetic diversity. In this studay, in order to explore the feasibility to correct the pedigree recording by constructing a molecular genealogy, we selected out 61 Laiwu black goats and 212 Laoshan dairy goats, and selected out 13 polymorphism microsatellites from 25 microsatellites of sheep ,to study paternity testing and molecular pedigree construction, and evaluat the reliability of them. Cervus2.0 was used for paternity testing ,and computed the allele frequency, polymorphism information content (PIC), observed heterozygosity (Ho), expected heterozygosity (He), exclusion probability (EP), combined exclusion probability (CEP), and the Hardy-Weinberg equilibrium was tested also. Pedigraph2.2 software was used to build parent-based family genealogy and group molecular genealogy, analysising the factors on the impact of paternity testing by removing the site and the parent informations , the genetic characteristics of the molecular pedigree was analysised by the use of Molkin vs3.0, MEGA4 and GENECLASS2 software. The results show that:(1)The 13 microsatellite loci we selected were used in the black goats and dairy goats in two groups, and we detected the average allele allele were 7.67 and 5.75, respectively.Except for BM302 of Laiwu Black goats. The PIC of all microsatellite was more 0.5, the mean value of PIC was 0.675, 0.678 respectively, the average expected heterozygosity are 0.712 and 0.730 respectively. 13 microsatellite loci can be used for parenty analysis.(2) The combined exclusion probability is 0.992072, 0.991889 respectively, when parents are both unknown, the confidence levels of both were more than 80%. It is 0.999842, 0.999797 respectively, when parents are both known, the confidence levels of both were more than 80%. Finally,we found the biological parent of 152 offspring from 109 candidate mothers, and construct 5 pedigree maps on basis of paternal strains, five individuals were found in both goat populations were not correspond to the recoding genealogy. (3) The results by removing the loci show that: the percentage lowing is small with the loci reducing, when PIC is higher, the CEP1 and CEP2 can achieve 99% on 9 microsatellite loci when polymorphism information content were kept at 0.7 or so, and there are 11 when PIC is 0.6. The correlate analysis of genetic parameters show that, single-parent exclusion and two-parental exclusion were significantly related with the PIC, He, Ho and K, the largest correlation coefficient is with the PIC, and followed by He and Ho, the allele numbers (K) is the lowest. The results by the reduction of parent informations show that, the accuracy rate of testing father-child relationship is 100% in the case of knowning father-identification and more 50% mather-identification, the success rate is only 50% when father-identification is known.(4) Gnetic distance between families and genetic parameters in 5 families were analyzed with Molkin vs3.0 software, using MEGA4 genetic analysis software, based on Kinship Coefficient matrix and shared allele distance matrix , we drawn NJ phylogenetic tree of 5 families. When the level is 99%, we detected 13 the first generation migrants in five families by the use of GENECLASS2 software, they are 4.76% of total allocation of samples. In conclusion, there are certain genetic distance between different families, and abundant genetic variation in 5 families, the genetic distance between individuals within families is more than 0.4. The average genetic relationship of different individual in different family in Laoshan dairy goats group is more bigger Significantly than Laiwu black goats group, this is correspond to buy social groups of Laiwu black goats group to supplement and keep Multiple family.The construction of molecular genealogy in this study hare a high reliability, it can provide favorable information to prevent the inbreeding and the degradation of group germplasm, Meanwhile, the studay can provid a usefus reference about polymorphic microsatellite markers for the local goat breeds.