Study On Molecular Markers Of The Prolificacy In Hu Sheep

Four sheep breeds (Hu sheep, Small Tail Han sheep, Dorset, and Texel) were tested for the polymorphisms of the FecXI and FecXL mutation in BMP15 by PCR-SSCP, and eleven microsatellite markers on chrosome 6 were selected for amplifing DNA from 107 Hu sheep ewes in this study. Our objective was to search for DNA markers correlated with litter trait in Hu sheep and provide genetic information for the selection of high fecundity strains of Hu sheep and outbreeding between Hu sheep and the other sheeps.These results showed that:1. Ear sample of 139 Hu sheep,10 Small Tail Han sheep,17 Dorset, and 9 Texel were tested by PCR-SSCP analysis and sequencing, there was no FecXI or FecxL mutation in any of the breeds tested. These results suggested that there may be no correlation between FecXI or FecXL allele and high fecundity of Hu sheep and Small Tail Han sheep, although more samples were required to confirm it.2. The eleven microsatellite loci were selected across the chrosome 6 with the interval between 6 CM and 20 CM to test DNA samples of 107 Hu sheep ewes. These results showed that:In the ten loci, the mean number of alleles was 6.3; the mean effective number of alleles was 4.4182; the mean expected heterozygosity was 0.3844; the mean observed heterozygosity was 0.7652; and the mean polymorphic information content was 0.743 of the ten loci, although there was no polymorphisms of MCMA9 in 107 Hu sheep ewes. The observed heterozygosities of each locus were less than the expected heterozygosities, the allele frequencies were not in hardy-weinberg equilibrium in the sampled population. This implied that the proportion of homozygotes was very high, which was corresponded with artificial selection mating implemented in the population.3. One ANOVA analysis was performed for the litter size of the Hu sheep ewes and their genotypes. These results showed that the mean litter size of the genotype 111/116bp and 120/120bp was significantly larger than that of 114/116bp in BM143, the mean litter size of the genotype 99/103bp was significantly larger than that of 85/95bp and 91/95bp in MCM53.