SNP analysis in Fatty Acid Synthase and Adiponectin genes in Italian pig breeds

We investigated polymorphisms in pig Fatty Acid Synthase (FASN) and Adiponectin (ADN or ACDC, Adipocyte C1q and collagene-domain-like) genes, candidates for meat and carcass quality, analysing DNA samples of main and local pig breeds reared in Italy. FASN is an enzyme that plays a central role in fatty acid biosynthesis catalysing the production of long-chain saturated fatty acids. FASN gene has been assigned to SSC 12p1.5 and a T>C polymorphism in the fourth exon was found at position 265 of sequence AY183428. Adiponectin is a fat derived hormone involved in insulin sensitivity, in lipid and glucose metabolism. The gene was mapped on SSC 13 at 53.6 cM, in a region containing a QTL for intramuscolar fat. In this gene a G>A missense mutation within the 60th codon, determining a Val-Ile substitution in the protein, has been reported in literature. The T>C polymorphisms of FASN, and the G>A mutation of ADN genes were studied by PCR-RFLP. All analysed breeds showed the polymorphisms, except for Hampshire samples that presented only the G allele at ADN locus. In FASN locus the allele C was the most frequent in the analysed breeds and its value was higher than 0.80 in Duroc, Belgian Landrace, Pietrain and Cinta Senese samples.Two groups of Italian Large White pigs with extreme divergent genetic index (50 highest and 50 lowest) for backfat thickness were genotyped for FASN polymorphism. Significant differences of allele frequencies between the groups were found (P=0.016). In ADN locus G allele was the most frequent in the examined breeds with values ranging from 0.85 (Duroc) to 0.99 (Italian Large White). The sequencing of PCR products obtained using three different primer pairs allowed to determine the sequence of part of intron 1, exon 2, intron 2 and almost complete encoding region of 3th and last exon of ADN gene. Additional SNPs were detected in the introns of the gene by sequencing the DNA of pigs of six different breeds.