In a population at Hardy-Weinberg equilibrium, if the frequency of the dominant allele T is 0.80, what percentage has short tail feathers?

To solve this question, it’s important to understand the concept of Hardy-Weinberg equilibrium and how allele frequencies relate to phenotypic expressions in a population.

In this scenario, you are given that the frequency of the dominant allele T is 0.80. In Hardy-Weinberg terms, the frequency of the dominant allele (T) is represented as p, and the frequency of the recessive allele (t) is represented as q. Since there are only two alleles, the relationship between p and q is as follows:

p + q = 1.

This means if the frequency of the dominant allele (T) is 0.80, you can calculate the frequency of the recessive allele (t):

q = 1 - p = 1 - 0.80 = 0.20.

The phenotype for short tail feathers corresponds to the homozygous recessive genotype (tt). The frequency of this genotype in the population can be determined using the Hardy-Weinberg formula for genotype frequencies, which is:

q² = (frequency of recessive phenotype).

Substituting q into this equation gives you:

q² = (0.20)² = 0.04.

To express this as a percentage