Studies On Mapping The QTLs By SNPs Markers Of Chromosome 4 And The Association Between SNPs Of DECR1 Gene And Economic Traits In Swine

The SNPs of 12 genes in chromosome 4 were studied by PCR-RFLP,PCR-SSCP and sequencing methods, with a reference family with 212 pigs provided by Danmark Royal veterinary University, and the linkage map of the markers was built by "BUILD" and "ALL" procedures, afterwards, the genotypes and their recombination were tested by "CHROMPIC" procedure. The association between the linkage map spanning 115.1cM with 12 SNP markers and meat quality, and slaugter traits were analysed by mixed model, the results showed as follows:1. The genetic linkage map spanned 115.1cM including 12 SNP markers, such as ZNF644 (9.5cM), SLC35A3 (25.3 cM), SORT1 (41.7 cM), ATP5F1 (51.6 cM cM), RAPIA.(57.2 cM), GDAP2 (66.8 cM), PRKAB2 (74.5 cM), PMVK (81.4 cM), PMF1 (89.9 cM), NDUFS2 (99.2 cM), CA8 (105.7 cM), SDC2 (124.6 cM).2. There was a QTL in chromosome 4 associated with pHI (P<0.05). the QTL was mapped between PMVK and NDUFS2, the average relative position was p=0.58±0.37 and it was located in 94.73cM in the linkage map. The additive and dominant effects of the QTL on PHI were 0.347±0.136 (P＜0.05) and 0.322±0.114(P <0.05), separately.3. There was also another QTL in chromosome 4 associated with pHU (P<0.05). the QTL was mapped between ATP5F1 and RAPIA, the average relative position was p= 0.39±0.16 and it was located in 55.61cM in the linkage map. The additive and dominant effects of the QTL on PHU were 0.318±0.129 (P<0.05) and 0.299±0.107 (P<0.05), separately.4. There was also a QTL in chromosome 4 associated with backfat (P<0.05). the QTL was mapped between SORT1 and GDAP2, the average relative position was p= 0.62±0.39 and it was located in 50.26 cM in the linkage map. The additive and dominant effects of the QTL on backfat were 0.705±0.714mm (P<0.05) and 0.681±0.802 mm (P<0.05), separately.5. There was also a QTL in chromosome 4 associated with slaughter weight (SWT) and average daily slaughter gain (ADSG) (P<0.05). the QTL was mapped between ATP5F1 and GDAP2, the average relative position wasρ=0.47±0.32 and it was located in 65.10cM in the linkage map. The additive and dominant effects of the QTL on ADSG were 0.023±0.008 kg/d (P<0.05) and 0.017±0.007kg/d (P<0.05), separately.Three hundreds and twenty seven Yorkshire, Landrace and Duroc pigs were analysed to screen the SNPs in 6-10 exon of mitochondrial 2,4-dienoyl-CoA reductase 1 (DECR1) gene. Two SNPs were screened in exon 6 and exon 8 by the asymmetric PCR-SSCP method, the association between the 2 SNPs and meat quality, and slaughter traits in Yorkshire and Landrace pigs, were analysed, the results were showed as follows:1. The homology analysis of DECR1 mRNA express sequences on swine, bovine, mus musculus, Rattus norvegicusand human using DNAStar software showed, the homology of swine with bovine, mus musculus, rattus norvegicus and human were 89.7%,82.5%,81.6%,89.8%, separately. Swine had the higest homology with human, the second homology with bovine, the lowest homology with rattus norvegicus.2. The primers were designed accroding to human DECR1 gene to screen the SNPs. Two SNPs were screened in exon 6 and exon 8 by PCR-SSCP method.3. The polymorphism of the SNP in exon 6 of 3 breeds was studied, and 3 genotypes (CC, CT, TT) were tested in 3 breeds, and allele C was the advantageous allele. There were also 3 genotypes (CC,CG,GG) in the SNP of exon6 in 3 breeds, and allele A was the advantageous allele.4. The association analysis between SNP of exon6 and meat quality, and slaughter tarits in Yorkshire showed:(1) The pH value of samples with genotypes CC and CT were significanf higher than that of genotype TT (P<0.05). (2) The water lose percentage of samples with genotype CC were different with that of genotype TT (P <0.05). (3) The backfact of samples with genotype CC were lower than that of genotype TT (P<0.05), the backfact of samples with genotype CC were also different with that of genotype CT (P<0.05). The association analysis between SNP of exon6 and meat quality, and slaughter tarits in Landrace showed:(1) The pH value of samples with genotypes CC and CT were higher than that of genotype TT (P<0.05). (2) The backfact of samples with genotype CC were lower than that of genotype TT (P<0.05), the backfact of samples with genotype CC were also different with that of genotype CT (P<0.05). (3) The eyes muscle area of samples with genotype CC were different with that of genotype TT (P<0.05).5. The association analysis between SNP of exon8 and meat quality, and slaughter tarits in Yorkshire showed:(1) The marbling grading of samples with genotype CG were differrent with that of genotype GG (P<0.05). (2) The carcass length of samples with genotypes CC and CG were higher than that of genotype GG (P<0.05). The association analysis between SNP of exon8 and meat quality, and slaughter tarits in Landrace showed:(1) The meat colour grade of samples with genotypes CC and CG were different with that of genotype GG (P<0.05). (2) The slaughter percentage of samples with genotypes CC and CG were higher than that of genotype GG (P<0.05).