Question

In a population, 36% consists of homozygous recessive genotypes (aa). Then the frequency of allele “a” will be

• A. 0%
• B. 20%
• C. 60%
• D. 70%

Answer 1

The correct option is C 60%

According to Hardy - Weinberg equilibrium

$p^2+2\mathrm{pq}+q^2=1$ where,

p = frequency of the dominant allele in the population

q = frequency of the recessive allele in the population

$p^2$ = percentage of homozygous dominant individuals

$q^2$ = percentage of homozygous recessive individuals

2pq = percentage of heterozygous individuals

The frequency of aa is 36%,

Therefore, $q^2$ = 0.36,

then q = 0.6

Since q equals the frequency of the ‘a’ allele, then the frequency is 60%.