Question

The gene frequency for an X-linked recessive disease is 1 in 1,000 in the general population. What is the frequency of affected males in this population?

(A) 1 in 10
(B) 1 in 100
(C) 1 in 500
(D) 1 in 1,000
(E) 1 in 2,000

Answer 1

The frequency of males affected by an X-linked recessive disease when the gene frequency is 1 in 1,000 is also 1 in 1,000 because each male has only one X chromosome.

Step-by-step explanation:

The frequency of affected males in a population where an X-linked recessive disease gene frequency is 1 in 1,000 would be the same as the gene frequency itself since males have only one X chromosome. This means that if a male inherits the X chromosome with the recessive disease allele, he will be affected because males do not have another X chromosome to potentially carry a normal allele that could mask the recessive one. Therefore, the frequency of affected males is 1 in 1,000 (Option D).