An association between the MyoD gene polymorphisms and carcass traits in two- and three-breed crossbred pigs.

The objective of the study was to analyse the relations between the porcine MyoD genotypes and carcass traits in two-breed (Polish Large White × Polish Landrace) and three-breed (Polish Large White × Polish Landrace sows mated to Pietrain boars) crossbreds both being the most common in Poland. A total of 113 animals (78 twoand 35 three-breed crossbreds) were included. The genotypes were defined at the following MyoD loci: MYOD1 (C489T), MYF5 (A65C) and MYF6 (C920G and A942C). Dissection of carcass-sides was performed according to the method recommended by Walstra and Merkus in 1995. The CC genotype at the MYOD1 locus appeared to be most favourable for some traits characterizing carcass muscling, independently on a type of crossbred and similarly to that observed in authors’ earlier study on pure PLW and PL breeds. The effect of different genotypes at MYF5 and MYF6 loci on a value of certain carcass traits was found to be affected by the type of crossbred. It may suggest that the SNPs in these genes are not causative mutations, but might be considered as genetic markers of other mutations influencing the analysed carcass traits.