Question

For an X-linked recessive trait, 9% of the females in the population are affected. What percent of the males would be affected? What percentage of the population is represented by carriers? Show your work and circle your answers.

Answer 1

Frequency of affected males: 30%

Carriers are represented by heterozygous females: 42%

Step-by-step explanation:

According to the Hardy–Weinberg principle:

1 = q2 + 2pq + p2

1 = q + p

p2 = 0.09 >> p = 0.3

Males have only one X chromosome, thereby the frequency of affected males is the allele frequency >> 0.3 (30%)

q = p - 1= 0.7

Carriers are females that are heterozygous >>

2 pq = 2 x 0.3 x 0.7 = 0.42 >>> 42%