Linkage and QTL mapping for Sus scrofa chromosome 4

Linkage maps of Sus scrofa chromosome 4 (SSC4) based on 19 markers were similar in lengths for three F-2-families [Wild Boar (W), Meishan (M) and Pietrain (P) crosses] and in agreement with the previously published maps. Quantitative trait loci (QTLs) on SSC4 affect mainly muscle and fat mass. Compared with others, Pietrain alleles were associated with longer carcass, higher body weight and higher meat content. In all three families, the profiles of F ratio values for these traits showed peaks close to the positions of candidate genes V-ATPase, ATP1A2 and ATP1B1. Additional more proximally mapped QTLs, significant at the p<0.05 chromosome-wide level, were found in the M x P and W x P families. The W x M family revealed highly significant QTLs located in the vicinity of AMPD1 and NGFB. The SSC4 QTLs explained up to 12% of F-2 phenotypic variance.