A grandfather has an X-linked disease.His wife does not have the disease and she is not a carrier for it.What is the probability that their daughter's sons will have the disease?

Question

Quizplus · Accepted Answer

Since the disease is X-linked and the grandfather has it, all of his daughters will be carriers because they receive his affected X chromosome. The wife does not have the disease or carry it, so she provides a normal X chromosome. Their daughters, being carriers, have a 50% chance of passing the affected X chromosome to their sons, who would then express the disease because males have only one X chromosome.

A Grandfather Has an X-Linked Disease