Question

Brown eye color (B) is dominant and blue eye color (b) is recessive. In one school, 128 students have brown eyes and 72 students have blue eyes (bb). Which of the following correctly represents the possible frequencies of each genotype?

(p + q = 1, p2 + 2pq + q2 = 1)

Answer 1

Answer: The correct answer is -

p2 + 2pq + q2 = 1

Step-by-step explanation:

The given equation p2 + 2pq + q2 = 1 is described as equation for Hardy Weinberg's equilibrium, according to which the frequency of genotype and allele in a population remains constant over generations.

In the equation -

p2 + 2pq + q2 = 1

p2 represents the frequency homozygous dominant genotype (such as BB for Brown eyes),

2pq is the frequency of heterozygous genotype (such as Bb) and q2 is the frequency of homozygous recessive genotype (such as bb for blue eyes).

Thus, in the stated question, the frequency of each genotype is correctly represented by the equation p2 + 2pq + q2 = 1

Answer 2

p + q = 1 correctly represents the possible frequencies of each genotype.
The sum of the allele frequencies at the locus must be equals to 1,
so p + q = 1