| Reproductive traits of swine are important economic traits, which highly influence the economic efficiency of pig production. Previously, prolactin receptor (PRLR) gene and follicle-stimulating hormone btea subunit (FSHβ) gene are the major genes or candidate genes which influence porcine reproductive performance. The objective of this investigation was to contribute to the knowledge of genetic variations of PRLR gene and FSHβ gene, and their influences on porcine reproductive performance and other performances. And the application of these two genes during the process of pig breeding was also discussed.1. In present study, according to the aligment of the published mRNA or cDNA sequences of PRLR gene in human, house mouse, rabbit, cow, and pig, we designed three PCR primers to amplify the porcine PRLR gene's fragment which spaned from exon8 to exonlO. Sequencing results showed that this fragment spaned 3637bp, and included the partial sequence of exon8 of 68bp, intron8 of 507bp, exon9 of 70bp, intron9 of 1816bp, and all encoding region of exonlO and partial 3' untranslated region of 1023bp and 153bp respectively.2. By means of the sequence of the part in PRLR gene from exon8 to exon9, PCR primers named by P4, P5 and P6 were designed to amplify the fragments, and polymorphism in this part was detected by using PCR-SSCP and cloning and sequencing techniques. Fifteen mutations were detected in intron8 of PRLR gene, which were the single nucleotide substitution of C→ T at the position of 26, 54, 99, 292, A → G at the position of 47, 68, 244, 410, G→ A at the position of 63, 402, T→ C at the position of 153, 421,483, an insertion mutation of AAA at the position of 134, a deletion of AACC at the position of 412.By means of the exonlO sequence in PRLR gene, PCR primers of P7 and P8 were designed to detect the polymorphism of this part. No mutation was detected in the part of P7 amplification. Three mutations were detected in the part of P8 amplification. A null mutation of T→ C at the position of 766 of exon10 in PRLR gene caused Hpall-RFLP. A missense mutation of A→ G was detected at the position of 935 of exonlO, which could cause the substitution of Gly for Ser at this position in PRLR molecule. And it caused Alu I -RFLP too. A single nucleotide substitution of A→ G was at the position of 1138 of 3'-untanslated region in the PRLR gene.3. A total of 381 litter records from 127 sows from Duroc, Landrace, Large White and Shanxi White were analyzed to determine whether the different polymorphic locus of PRLR gene influenced total number born and number born alive by using the least square analysis. We were not able to find significant associations between the polymorphic markers of P4 and P5 and phenotypes studied (P>0.05). At the polymorphic locus of P6, the total number born at the first parity of sows with AA, AB, AC and BB genotype was significantly more compared to BC sows (P<0.05). And AC sows have the most piglets of 10.69, and 9.83 pigs for AA sows was just less than AC. Considering its effects on other traits, we thought the allele A was favorable allele for improving litter size, and the AA individuals have advantages in litter size. The difference for total number born and number born alive of different genotype sows at P8 polymorphic locus was not signficant, but have a trend of AA>AB>BB, which was in accordance with some reported studied results.4. A total of 369 piglets records at birth and 152 replacement pigs records at the age of six months from 4 and 5 generation during the breeding process of Shanxi White were analyzed to determine whether the different polymorphic locus of PRLR gene influenced birth weight, total nipples, body weight at six-month and other body measurement traits at six-month by using the least square analysis. No signficant difference was detected in P4 different genotypes. And there were significant difference for nipple number, body weight... |
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