In a population of 10000 individuals 200 men are afflicted w

In a population of 10,000 individuals, 200 men are afflicted with a recessive, X-linked disease. How many woman would be expected to be afflicted in this population? (Assume the population is 50% men and 50% women.

a.) 8

b.) 100

c.) 4

d.) 24

Solution

Answer: 4

Reason:

As the males carry only one X-chromosome. The number of affected males is = the frequency of recessive allele.

Thus, the frequency of recessive allele, q is = 200/10000 = 0.02

The frequency of dominant allele, p is = 1-0.02 = 0.98

The frequency of affected females is, q2 = 0.02*0.02 = 4