In humans, muscular dystrophy is a condition in which the muscles waste away during early life, resulting in death in the early teens. It is due to recessive sec-linked gene. A certain couple have 5 children- 3 boys, ages one, three and ten; and 2 girls, ages five and seven. The oldest boy show the symptoms of this disease. Suppose you are their family physician and they come to you for advice. What would you tell them about the chances of their other children developing the disease?

Answer 1

Since it is a recessive X-linked gene, the father definitely does not have the MD gene. Since the mother does not have MD, she is heterozygous. There is a 50% chance of the other boys getting the MD gene and the disease and a 50% chance of the daughters being carriers, but no chance of them having the disease.

Answer 2

Thank you :)