Figure 1. Manhattan plots for QTL affecting facial wrinkles in Erhualian pigs. (A) Genome-wide association study (GWAS) plot for wrinkle pixel ratio. (B) GWAS plot for wrinkle score. (C) Meta-trait GWAS plot for facial wrinkles. (D) Boxplot for the significant SNPs grouped by different genotypes. The dashed line delineates the suggestive significance threshold (P = 2.78 × 10-5); the solid line delineates the genome-wide significant threshold (P = 1.39 × 10-6).