Final answer:
In a genetic model with two alleles p and q, the sum of their frequencies equals 1. With p given as 0.22, the frequency of q is 1 minus p, which equals 0.78. The correct answer is A. 0.78.
Step-by-step explanation:
The subject of this question is genetics, specifically allele frequencies in a population. In a genetic model where a trait has only two alleles, represented by p and q, the sum of the frequencies of these alleles should equal 1 (p + q = 1). This is based on the principles of the Hardy-Weinberg equilibrium, which describes a stable population in terms of allele frequencies. Given that allele p has a frequency of 0.22 (p = 0.22), we can calculate q by subtracting p from 1:
q = 1 - p
q = 1 - 0.22
q = 0.78
Therefore, the frequency of allele q is 0.78. The correct answer is A. 0.78.