Full color (D) in domestic cats is dominant over dilute color (d). Out of 325 cats observed, 194 have full color and 131 have dilute color. If these cats are in Hardy-Weinberg equilibrium for the dilution locus, calculate the frequency of the d allele. Use three decimal places for your answer.

frequency of d allele = 0.635

Explanation:

If p = frequency of dominant allele and q = frequency of recessive allele

According to Hardy-Weinberg equilibrium:

p + q = 1 and p² + 2pq + q² = 1

where p² = frequency of homozygous dominant genotype

q² = frequency of homozygous recessive genotype

and 2pq = frequency of heterozygous genotype

Here,

q² = d² = 131/325 = 0.403

so q = d = √0.40 = 0.6348 = 0.635

Hence frequency of d allele = 0.635