Question

Frequency of recessive allele is 0.2. What is the frequency of homozygous dominant?

• A. 0.64
• B. 0.32
• C. 0.8
• D. 0.064

Answer 1

The correct option is A 0.64

According to the Hardy-Weinberg law, the allele and genotype frequencies in a population remain constant under the absence of factors responsible for evolution. The sum of the frequencies is equal to one.

(p + q)${}^2$ = $p^2$ + 2pq + $q^2$ = 1.

Here, p is the frequency of the dominant allele, $p^2$ is the frequency of homozygous dominants, q is the frequency of recessive allele and $q^2$ is the frequency of homozygous recessive individuals. The 2pq in equation shows frequency of heterozygotes in the population.

In the question, the frequency of the recessive allele is (q) = (0.2). Since p+q=1; hence, frequency of dominant allele= (p = 1-0.2 = 0.8). And the frequency of homozygous dominant = $p^2$=(${0.8}^2$) = 0.64.

So, the correct answer is '0.64'