Major genes of eye color and hair color linked to LU and SE.

Eye color and hair color were studied in a large Danish family material, tested earlier for a comprehensive set of genetic marker systems. We found strong evidence for linkage of "green eye color" or GEY to the Lutheran-Secretor systems (combined lod score 9.19). This would appear to identify a major gene with influence towards "green eye color". We also found evidence for linkage of GEY to "brown hair color" or BRHC (lod score 5.06), which would appear to identify a second major gene influence in the same region of chromosome 19. Concerning the obvious association in the general population between eye color and hair color which could imitate linkage if it were reflected within sibships, we did not recognize any such intrafamilial association; in the pooled informative sibships GEY and BRHC were independently distributed (as were LU-SE and GEY).