Summary of the genetic constitution as regards the FAT1 region of the backcross animals used for QTL analysis. The QTL status for each animal are presented; ++ = sire showing highly significant QTL effect; + = sire showing significant QTL effect; - = sire deduced to be not segregating for FAT1; ? = QTL data inconclusive; n.t. = not tested for QTL segregation. The refined FAT1 interval is indicated by vertical arrows and determined by the boars BC365, BC7161 and BC7333, all segregating for the QTL. The map distances are from the linkage map by Moller et al. . BCXy: BCX = backcross generation X, y = pig identity number.