Final answer:
For a trait with two alleles p and q, if p equals 0.22, then q equals 0.78 according to the Hardy-Weinberg principle that states p + q = 1. (option A is the correct answer).
Step-by-step explanation:
In a trait with two alleles, the sum of the allele frequencies is always equal to 1. Since p represents one allele and equals 0.22, q, representing the other allele, can be calculated by subtracting p from 1. Thus, q = 1 - p = 1 - 0.22 = 0.78.
In population genetics, the Hardy-Weinberg equilibrium principle states that the frequencies of alleles in a population remain constant from generation to generation in the absence of other influences. This equilibrium allows us to make predictions about allele frequencies, such as calculating one allele's frequency when the other is known. In this case, knowing p allows us to determine q, providing insights into the genetic makeup of the population.
In this population, the frequency of allele q is 0.78, and these calculations align with the Hardy-Weinberg equilibrium, offering valuable insights into the genetic composition of the population.