Abstract
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‐baired 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=0.05 in maies and=0.24 in females for the MNS blood group System; this assigns a major locus for red hair to chromosome 4.