Association study in the IBS region using a Japanese Black population. (A) Association of the SNPs with carcass weight. A hundred and eighty-seven steers selected from the 4.7% extremes of 7990 steers were genotyped. P-values were calculated by Fisher's exact test for independence. (B) Genes located in the 591-kb region. (C) LD map. The LD was calculated for the 187 steers.