Study On Effects Of ESR, RYR1 Polymorphisms On Number Of Piglets Born Alive And SNP Detection Of Four Genes

625 pigs in six breeds including exotic breeds (Duroc, Landrace and Large white) and domestic breeds (Qingping pigs, small Meishan pigs and Jinhua pigs) were employed to investigate single nucleotide polymorphisms (SNPs) of ESR and RYR1 genes respectively by using PCR-RFLP technique. In this study, allele and genotype frequencies were calculated for each breed. All data were analyzed with SAS8.0. The association between polymorphisms of two genes and number of piglets born alive (NBA) was analyzed in sows. Effects of RYR1 genotypes on NBA were analyzed in boars. Effects on NBA were preliminary estimated by considering combined genotypes of two genes. Effects of RYR1 genotypes together in both sows and boars were employed to correlate with NBA. We established the basis of detecting method, which can be used to identify mutations of ESR and RYR1 simultaneously. Four genes, which based on their possible functions on semen quality, were chosen to look for new SNPs. The results were described as follows:1. The duplex PCR and double digestion technique were established to detect polymorphisms of ESR and RYR1 simultaneously.2. Allele and genotype frequencies were calculated in six breeds. In the ESR gene, Allele B in the domestic breeds was higher than the exotic breeds. The gene frequency of allele B in Qingping, small Meishan, Jinhua was 0.884, 0.744,0.617 respectively. In the RYR1 gene, No nn genotype was found in the domestic breeds, however there was n allele (f=0.247) in the exotic breeds.3. In the ESR gene, results of association of polymorphisms with litter size showed that NBA with genotype BB was higher than those with AB and AA in the Large White breed.4. In the RYR1 gene, we analyzed the association of polymorphisms with litter size. NBA per parity with genotype NN was higher than those with the other genotypes. In Duroc breed, NBA in the second parity with genotype NN was higher than that with genotype nn with significant differences (p<0.05). And it reached extreme significant differences (p<0.01) in exotic breeds.5. Effects of combined genotypes of ESR and RYR1 were analyzed to correlate with NBA in exotic breeds. The results showed that genotype with AB-NN was higher (1.74 piglets) than that with AA-nn (p<0.05) for NBA in per parity.