Question

An inherited defect in a certain receptor protein confers resistance to infection with HIV1 (human immunodeficiency virus 1, the cause of AIDS). Resistant people are homozygous recessive and are found at a frequency of 1 percent in the population. Assuming Hardy-Weinberg proportions, determine the frequency of heterozygous genotypes.

Answer 1

The frequency of heterozygous genotypes for the inherited defect is approximately 18 percent.

Step-by-step explanation:

The question is asking about the frequency of heterozygous genotypes for an inherited defect in a receptor protein that confers resistance to HIV infection. According to the information provided, people who are resistant to HIV infection are homozygous recessive, meaning they have two copies of the recessive allele. The frequency of homozygous recessive individuals in the population is given as 1 percent. Assuming Hardy-Weinberg proportions, we can determine the frequency of heterozygous genotypes using the equation: 2pq, where p is the frequency of the dominant allele and q is the frequency of the recessive allele.

Given that the homozygous recessive frequency is 1 percent, we can calculate the frequency of the recessive allele (q) by taking the square root of 1 percent (0.01). This gives us a q value of approximately 0.1. To find the frequency of the dominant allele (p), we subtract q from 1, which gives us a p value of 0.9.

Using the equation 2pq, we can now calculate the frequency of heterozygous genotypes: 2 * 0.9 * 0.1 = 0.18, or 18 percent. Therefore, the frequency of heterozygous genotypes for this inherited defect is approximately 18 percent.