If the carrier frequency in the general population is 11000

If the carrier frequency in the general population is 1/1000 what is the probability that individual IV-2 has an affected son? Select one: a. 1/8000 b. 1/160,000 c. 1/16 d. 1/4000 e. 1/16,000

Solution

Choice d.

Reason: It has been stated in the information that the carrier frequency of the disease is 1/1000 which means that there are 1/1000 chances that the disease is carried by an individual. Thus, for the given pedigree, the F1 has carrier frequency of 1/1000. Further, the F2 will indeed carry an allele from their parents and this carried over allele will be transferred to F3 as well. Thus, the carrier frequency for F3 will be 1/2 * 1/2 in this case (for F2 and F3).

Thus, the final carrier frequency for F4 will be 1/1000 * 1/2 * 1/2 or 1/4000.