Question

Duchene’s Muscular Dystrophy (DMD) is a severe disorder that results in degeneration of skeletal muscle tissue. Affected individuals typically do not survive past their late twenties. The disorder is caused by a mutation in the dystrophin gene on the X-chromosome. The disorder primarily affects males. Males who have the condition are very unlikely to have children of their own. Females are very rarely affected by the mutation, but they may carry it. Draw a Punnett square that reflects the most likely scenario for how a healthy couple could produce a child with DMD. What gender among the offspring is affected and why?

Answer 1

Answer:Explanation:

The mother is a carrier, meaning she has one normal X-chromosome (X^X) and one with the DMD mutation (X^Y).

The father is healthy and has one normal X-chromosome (X^X) and one Y-chromosome (Y).

The Punnett square shows the possible combinations of their gametes.

The offspring have a 50% chance of receiving the normal X-chromosome from the mother (X^X) and a 50% chance of receiving the Y-chromosome from the father (Y).

Therefore, the offspring have a 50% chance of being male (XY) and unaffected, and a 50% chance of being female (XX) and being a carrier of the DMD mutation.

Among the offspring, the male children (XY) are affected by DMD because they inherit the mutated X-chromosome from the mother. This disorder primarily affects males because they have only one X-chromosome, and if it carries the mutation, they will express the disorder. Females, on the other hand, would need to inherit the mutated X-chromosome from both parents to be affected by DMD, making it rare for them to be directly affected. However, they can be carriers and potentially pass on the mutation to their offspring.

Step-by-step explanation: