Major locus for red hair color linked to MNS blood groups on chromosome 4

Red hair color (RHC) was studied in a Danish material of normal families that was tested earlier for 65 marker systems. We found 4.85% of the parents to be red-haired or to have been so early in life. Scoring RHC for linkage as an autosomal dominant against blond and as hypostatic to dark hair gave a lod score of z = 5.50 at theta = 0.05 in males and theta = 0.24 in females for the MNS blood group system; this assigns a major locus for red hair to chromosome 4.