ASSIGNMENT OF GENES-CODING FOR BROWN EYE COLOR (BEY2) AND BROWN HAIR COLOR (HCL3) ON CHROMOSOME 15Q

Brown eye colour (BEY), or total brown iris pigmentation is one of the most common phenotypes of iris colour. Data of eye colour as well as hair colour were obtained for linkage analysis through an enquiry in o ur family material of 832 families from Copenhagen area. By exclusion mapping with 80 markers in 120 segregating families and 290 markers in 5 segregating families, we obtained some indication of a locus BEY2 f or brown eye colour on chromosome 15. For possible confirmation, we se lected a total of 45 families from our DNA bank segregating for BEY. A ll these were tested for chromosome 15 markers in the area between D15 S11 and CYP19. We found a strong indication of tight linkage with the DNA polymorphism D15S165 (Z = 24.25; theta(M=F) = 0.010) and with the flanking markers D15S156 (Z = 14.04; theta(M=F) = 0.0.029) and D15S144 (Z = 12.99; theta(M=F): 0.060). BEYZ is assigned to the region 15q11- 15q21 by physically localized markers. A new locus for brown hair colo ur (HCL3) was localized by indication of linkage to BEY2 in our 45 fam ilies segregating for BEY (Z = 9.93; theta(M=F) = 0.10) The gene (DN10 or P) homologous to the pink-eye-dilution gene (p) in mice could be a candidate gene for BEY2 or for HCL3.