Analysis of the associations between polymorphisms in GNAS complex locus and growth, carcass and meat quality traits in pigs

Imprinted genes are interesting candidates for marker assisted selection in farm animals. One of them-GNAS complex locus is engaged in obesity pathogenesis in humans and mice. In our study, we identified new polymorphism in porcine GNAS gene (variable number of CT repeats, accession number: rs196952953) and found that this polymorphism is in linkage disequilibrum with GNAS AM490165:g.324C > T. Statistical analysis (GLM procedure), performed on 552 animals (Large White n = 258 and Landrace n = 269), revealed that deduced haplotypes and GNAS AM490165:g.324C > T are associated with growth performance and a few carcass traits, but not with feed intake. We observed significant additive effects of GNAS AM490165:g.324C > T genotype and haplotype 2 (C/278 bp) on test daily gain (TDG), average daily gain (ADG), number of days on test, age of the slaughter (P < 0.01) and FCR ratio (P < 0.05). Animals with two copies of C/278 haplotype had significantly higher: TDG, ADG, lower feed:gain ratio and faster reached the weight of 100 kg. When carcass traits were considered, significant associations between GNAS AM490165:g.324C > T polymorphism, haplotype 2 (C/278) and weight of ham with and without backfat and skin (WH) (WH2), length of the carcass, height and the width of the loin, meat percentage, weight of the main cuts were identified. The significant dominance effects of GNAS AM490165:g.324C > T polymorphism and haplotype 2 on WH and WH2 were observed (P < 0.05). When the two breeds were analyzed separately significant associations were observed for most of the traits in Landrace while in Large White the same trends were present but the differences were mostly not significant. Among meat quality traits we found significant association between haplotype and IMF content in Landrace (P < 0.03). Our results show for the first time that GNAS complex locus may modulate economically important traits in pigs.