For a locus with two alleles A and a in a population at risk

For a locus with two alleles (A and a) in a population at risk from an infections neurodegenerative disease, 16 people had genotype AA, 92 had genotype Aa, and 12 had genotype aa. Use the Hardy-Weinberg equation to determine whether this population appears to be evolving.

Solution

Frequency of AA genotype is = 16

Frequency of Aa genotype is = 92

Frequency of aa genotype is = 12

The frequency of allele, A = Frequency of AA + ½ (frequency of Aa) = 16/120 + 1/2(92/120) = 0.1333 + 0.3833 = 0.5166

The frequency of allele, a = Frequency of aa + ½ (frequency of Aa) = 12/120 + 1/2(92/120) = 0.1 + 0.3833 = 0.4833

The frequency of A + the frequency of a = 0.5166 + 0.4833 = 0.9999 = 1

Thus, the population is in Hardy-Weinberg equilibrium and not evolving.