Identification of SNPs in the porcine adiponectin gene

Adiponectin (referred to as ADN and ApM1) is a fat derived hormone involved in lipid and glucose metabolism. The pig gene, mapped on SSC 13, can be considered a putative functional and positional candidate gene for growth and for meat production and quality. The aim of this work is to search for variability in the porcine adiponectin gene and to analyse new polymorphisms in different breeds (Italian Large White, Italian Landrace, Duroc, Hampshire, Landrace Belga and Pietrain). Three primer pairs were designed in order to amplify and to sequence amplicons of approximately 1100 bp each. The three different PCR products allowed to determine the sequences corresponding to the terminal part of intron 1, the exon 2, the intron 2 and the almost complete encoding region of the 3th and last exon of the ADN gene. New SNPs were found both in exons and introns regions. In particular it was identified a G>A polymorphism within the exon 2, which determines the val-ile substitution in the collagen-like domain of the protein. To study this polymorphism a further primer pair was designed and a PCR-RFLP protocol was set up. The most frequent variant was the G in all the examined breeds. Differences in allelic frequencies between the six pig breeds were observed. The polymorphism identified will be useful to perform association studies with meat quality and production traits in pigs.