if 94 of a population is Dpositive using Hardy Weinberg calc

if 94% of a population is D-positive, using Hardy Weinberg calculation, what percenatge is heterozygous for the D antigen.

Solution

According to Hardy Weinberg law, p + q= 1 or (p+q)² = pp+ 2pq+ qq=1.Here we assume that p=D and q= d. so according to the law : D+d = 1,(as D = 0.94) so d =0.06. Now the heterozygous for the D antigen will be 2Dd = (2)(0.94)(0.06)=0.1128.the percetage will be 11.28%.