| Yunan black pig becomes a new lean breed through hybridization and horizontal. Local pig breeds - Huainan pig as female parent, Duroc of the United States as male parent. So far, the molecular studies of FSHβand PRLR genes of Yunan black pig hasn't happened. Yunan black pig as object of the study compared with three foreign pigs.The foreign pig including Duroc, Landrace and Yorkshire. The Study of this experiment contributed to the knowledge of polymorphism of PRLR and FSHβgenes, and its relationship with reproductive traits, in order to discuss the application of the two genes as molecular marker during the process of Yunan black pig breeding.1. Analysis with genetic variation in FSHβgene Design primers in intron1of FSHβgene which include inserted fragment,the result showed the inserted fragment of 277bp has a SNP(A-G) by sequencing. The polymorphisms of FSHβgene was analyzed by PCR-RFLP methods,the results showed: three alleles and six genotypes were found in four pig breeds.The research of Yunan black pig showed that the frequencies of allele A,B and C were 0.0738,0.6475 and 0.2787;the frequencies of genotype AA,AB,AC,BB,BC and CC were 0.0164,0.0246,0.0902,0.4426,0.3852 and 0.0410;polymorphism informantion content and heterozygosity were 0.3451 and 0.4434.The distribution of genotype was significant lower between Yunan black pig and foreign pig(P<0.01).The effects of combined genotypes of FSHβgene on litter size traits ,the results showed that CC genotype of Yunan black pig produced 2.67 TNB,2.79 NBA, more than AC genotype in the first parity(P<0.05); 2.03 TNB,2.14 NBA in the later parity(P<0.05),however, the effects of combined genotypes on TNB and NBA were not significant in foreign pig.2. Analysis with genetic variation in PRPR gene By means of the sequence of intron 9 and exon 10 of PRLR,PCR primers named by P1 and P2 were designed to amplify the fraqments. Five mutations (G756A, T892G, C924A, C1055G, T1078G) were detected in P1 locus by using cloning and sequencing techniques. The polymorphisms of P1 locus was analyzed by PCR-SSCP methods, three alleles and five genotypes were found without AB genotype.The research of Yunan black pig showed that the frequencies of allele A,B and C of P1 locus were 0.19,0.59 and 0.22;the frequencies of genotype AA,AC,BB,BC and CC were 0.16,0.06,0.50,0.19 and 0.09;polymorphism informantion content and heterozygosity were 0.5051 and 0.5675.The distribution of genotype was not significant between Yunan black pig and foreign pig.The effects of combined genotypes on TNB and NBA were not significant in Yunan boack pig,however, CC genotype of foreign pig produced 2.38 NBA, more than BC genotype in the first parity(P<0.05).The polymorphisms of P2 locus was analyzed by PCR-RFLP methods,the results show that two alleles and three genotypes were found.The research of Yunan black pig showed that the frequencies of allele A,B gene were 0.5811 and 0.4189;the frequencies of genotype AA,AB and BB were 0.3343,0.5135 and 0.1622;polymorphism informantion content and heterozygosity were 0.3683 and 0.4868.The distribution of genotype was not significant between Yunan black pig and foreign pig.The effects of combined genotypes of P2 locus on litter size traits ,the results showed that there was no significant differences between the different genotypes in TNB,NBA, but a trend of BB>AB>AA existed in the Yunan black pigs.BB genotype of foreign pig produced 2.04TNB,2.53 NBA, more than AB genotype in the later parity(P<0.05); AB genotype had 0.37kg of weaning weight more than those with AA,BB genotype (P<0.05).3. By means of the sequence of the part in PRLR gene from intron8 to intron9, PCR primers were designed. Fragment of 149bp obtained by PCR amplification, Exon 9 contains 75 bases. According to DNA sequencing the position 559 of intron 8 may have a new SNP(C / T), needs to be validated.CONCLUTIONS: 1. The distribution of genotype was significant lower between Yunan black pig and foreign pig(P<0.01). Polymorphism informantion content and genetic variation of Yunan black pig is rich, the CC individuals have advantages in litter size,but other pig breeds havn't this correlation.2. The distribution of genotype was not significant between Yunan black pig and foreign pig at P1,P2 loci of PRLR gene. Polymorphism informantion content and genetic variation of Yunan black pig is rich at the two loci, there was not significant associations between the polymorphic of P1 and P2 and genotypes studied in litter size. At P1 locus, four populations were not in Hardy-Weinberg equilibrium, CC individuals of foreign pig have advantages in NBA of the first parity. At P2 locus, BB individuals of foreign pig have advantages in litter size of the later parity.3. Exon9 of PRLR gene was amplified, amplified sequence may has a new SNP at intron8.
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