Mapping of the scaleless mutation. (A) Genome-wide absRAFdif values (calculated by contrasting sc/+ and sc/sc RAF values) of all 60 K SNPs in the GWMAS consortium chicken SNP array, plotted against genomic location. A peak of values is apparent on chromosome 4. (B) absRAFdif values on chromosome 4. Three SNPs located within a 1.25 Mb region (boxed area) gave absRAFdif values above 0.45, suggesting the location of the sc mutation. (C) Schematic of genes present within the 1.25 Mb region defined by mapping.