Effect of HMGA1 on Performance Traits in Duroc, Landrace and Yorkshire Pigs

The high mobility group AT-hook 1 (HMGA1) gene is reported to have an effect on growth, backfat thickness and lean depth in pigs. The objectives of this study were to estimate the frequency of HMGA1 gene in the major Canadian swine breeds and investigate the effect of polymorphism C576T on backfat thickness (BFT), lean depth (LD), average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR). Numbers of genotyped station-tested pigs (and T allele frequency) were 183 (0.14), 183 (0.11) and 232 (0.08) for Duroc, Landrace and Yorkshire breeds, respectively. The statistical model included HMGA1 genotype, breed, trial and breed by HMGA1 genotype as fixed effects. Age and weight at start of test were included as covariates and pen within trial, farm of origin within trial and birth litter were included as random effects. A significant effect of HMGA1 on BFT was observed (p≤0.05), where CC pigs had 0.6±0.2 mm more BFT than their CT counterparts (p<0.05).  The frequency of the T allele was too low for meaningful comparisons involving the TT genotype.  A significant interaction between HMGA1 and breed for LD and FCR was found (p<0.01), indicating that the effect of HMGA1 genotype on these traits varies depending on the breed. No significant effects were found for ADG or ADFI. A larger study is suggested to confirm the effects found in this study, to increase the number of TT genotypes and to assess the potential value of including HMGA1 genotype in swine genetic evaluation.