Colorblindness and gene flow in Alaskans

Twelve of 604 Alaskan schoolboys (2%) had defective red green vision. The frequency was still lower (1.1%) among boys whose maternal grandparents were both considered indigenous. Anomaloscopic diagnoses suggested that the mutant genes of indigenous Alaskans were those causing more severe defects while milder anomalies were introduced by European admixture. The differences in specific allele frequencies between Alaskans and Europeans seem paradoxical in terms of the theory of relaxed natural selection.