Question

Duchenne muscular dystrophy (DMD) is recessive sex (or X)-linked disorder, which causes muscle degeneration and premature death. A couple is pregnant with a boy and neither has DMD. The father’s family has no history of DMD, but the mother is unsure of her genetic family history as she was adopted. The mother decides to take advantage of some of the new genomic screening tests and learns information about a large number of her genes. She finds that she is a carrier of the DMD-affected allele.

A.           What is the mother’s genotype? Explain your reasoning.

B.           What is the father’s genotype? Explain your reasoning.

C.           Explain why DMD is more common in males than females

Answer 1

2) mother's genotype is carrier for disease X​​​​​​d​​​​​X as her genomic screening reveals that she is carrier and she does not have symptoms of disease.

3) father's genotype is normal XY as there is no history of disease in his family and he is also normal

4) DMD is X chromosome linked recessive disease. Since male have single X chromosome while Y Chromosome does not have any gene so whatever gene is present on X chromosome will always expressed that why male are more commonly affected.

while female is mostly carrier as they have another X chromosome which mostly have wild type gene so it will not allow to expressed recessive affected character.

Thanks..!