In a population of humans, the frequency of blue eyes is 0.09. if having blue eyes is the recessive phenotype, what is the frequency of the recessive allele?
a. 0.3
b. 0.9
c. 0.18
d. 0.36

The correct answer is-

a. 0.3

Explanation-

As per the question, the frequency of blue eyes (which is a recessive trait) is 0.09.

Let us consider the genotype for it be 'qq' ( q representing recessive allele) that produces blue eyes.

According to equation of Hardy Weinberg principle-

p²+ 2pq+ q² = 1

where p² represent the genotype for dominant trait and q² is the genotype for recessive trait.

p represents frequency of dominant allele and q is recessive allele frequency.

q² =  0.09

q = √0.09

  =  0.3

Thus, option a) 0.3 is the right answer.