Question

Colorblindness in humans is due to an X-linked recessive allele. Out of 500 men surveyed in a population, 20 were found to be colorblind. a. what is the allele frequency of the normal allele in the population? b. what percentage of the females in this population would be expected to be normal?

Answer 1

The allele frequency of the normal allele in the population is 0.96. Approximately 99.84% of females in this population would be expected to be normal.

Step-by-step explanation:

To determine the allele frequency of the normal allele, we need to first calculate the frequency of the colorblind allele. Since colorblindness is X-linked recessive, only males with the colorblind allele will exhibit the trait. Out of 500 men, 20 were colorblind, so the frequency of the colorblind allele can be calculated as 20/500 = 0.04.

Since males have only one X chromosome, the frequency of the colorblind allele is equal to the frequency of colorblind males. Therefore, the frequency of the normal allele can be found by subtracting the frequency of the colorblind allele from 1: 1 - 0.04 = 0.96.

Since the normal allele is on the X chromosome, females have two copies of the allele. In order for a female to be colorblind, both of her X chromosomes must carry the colorblind allele. The probability of both X chromosomes carrying the colorblind allele can be calculated as the square of the frequency of the colorblind allele: 0.04 * 0.04 = 0.0016.

To determine the percentage of females expected to be normal, we subtract the probability of being colorblind from 1 and multiply by 100: (1 - 0.0016) * 100 = 99.84%. Therefore, approximately 99.84% of females in this population would be expected to be normal.

Learn more about Colorblindness in humans