The presence of freckles is due to a dominant allele. Four percent of individuals in a population do not have freckles. Use the Hardy-Weinberg principle to calculate the percentage of individuals in this population who are homozygous dominant for freckles.

The Hardy-Weinberg principle describes the relationship between allele frequencies and genotype frequencies in a population that is not experiencing evolutionary changes (such as natural selection, genetic drift, migration, or mutation). It allows us to predict the genotype frequencies in a population when certain conditions are met.

In this scenario:

• The presence of freckles is due to a dominant allele.
• Let's denote the dominant allele for freckles as 'F' and the recessive allele as 'f'.
• Since the presence of freckles is due to a dominant allele, individuals with the genotype FF or Ff will have freckles, while individuals with the genotype ff will not have freckles.

Given:

• 4% of individuals in the population do not have freckles, which implies that they are homozygous recessive (ff).

Let p be the frequency of the dominant allele (F) and q be the frequency of the recessive allele (f).

Since 4% of individuals do not have freckles (ff), the frequency of the homozygous recessive genotype (ff) in the population is 0.04.

According to the Hardy-Weinberg equation:

p^2 + 2pq + q^2 = 1

Given that q^2 (frequency of ff genotype) is 0.04:

q^2 = 0.04

To find q (frequency of the recessive allele f), take the square root of both sides:

q = √0.04

q = 0.2

Since q represents the frequency of the recessive allele (f), and q^2 is the frequency of the homozygous recessive genotype (ff), we need to find the frequency of the dominant allele (p).

p = 1 - q

p = 1 - 0.2

p = 0.8

Now, to find the percentage of individuals who are homozygous dominant for freckles (genotype FF), square the frequency of the dominant allele (p^2):

p^2 = (0.8)^2

p^2 = 0.64

Convert the decimal to a percentage:

0.64 * 100 = 64%

Therefore, approximately 64% of individuals in this population are homozygous dominant (genotype FF) for freckles.