Polymorphisms Of DGAT1 And Ob Genes And Associations With Backfat Thickness In Pigs

DGAT1 and obese are very important genes controlling fat deposition in animals.The present study performed SNPs analysis in porcine DGAT1 and obese genes, examined their polymorphism in pig populations and estimated their effects on backfat thickness. The objective of this study is to find useful DNA markers for fat deposition.For DGAT1 gene, exon 6 to exon 8 of Laiwu DGAT1 was amplified, sequenced and deposited (GenBank accession number DQ289596).Two SNPs were identified at exon6 and exon 8, respectively. The structures of DGAT1 intron 6 and intron 7 were also analysed. The SNP located in DGAT1 exon 8 was analysed in Laiwu and Yorkshire pigs. Laiwu pigs were in a state of Hardy-Weinberg equilibrium (P>0.05), whereas in Yorkshire only genotype CC was detected. A deletion of adenosine (A), at -241 (relative to initiation codon ATG), designated as Del(A) allele, was found in Laiwu compared with Yorkshire (GenBank accession number DQ463321-22). We checked this mutation in Yorkshire, Yorkshire×Laiwu, Duroc and Laiwu pigs and found that the genotype frequency of Del(A)/ Del(A) is the highest in Laiwu pigs: all Laiwu pigs that were checked were homologous Del(A)/ Del(A). No deviation from Hardy-Weinberg equilibrium was detected in Yorkshire, Duroc and Yorkshire×Laiwu pigs. Across genotypes, on-test backfat thickness was not different (P>0.05); however, birth weight differs significantly (P<0.05). The additive and dominant effect on birth weight in Yorkshire×Laiwu is 0.09868kg and 0.04574kg, respectively.For porcine ob gene, we found a novel SNP in upstream elements of obese gene (G2835A) according to its position.We detected its distribution and analyzed its relationship with backfat thickness in Laiwu, Landrace,Yorkshire, Duroc, Yorkshire×Laiwu and commercial crossbred pigs. The results revealed that G allele was the lowest in Laiwu pigs(0.32),but was the highest in Duroc(0.93) .The Laiwu,Yorkshire,Doruc and commercial crossbred pigs were in a state of Hardy-Weinberg equilibrium(P>0.05).The backfat thickness...