Duchenne muscular dystrophy is sex-linked and usually affects only males. Victims of the disease become progressively weaker, starting early in life.

a. What is the probability that a woman whose brother has Duchenne's disease will have an affected child?

b. If your mother's brother (your uncle) had Duchenne's disease, what is the probability that you have received the allele?

c. If your father's brother had the disease, what is the probability that you have received the allele?

Question

Allie Atkins

Biology

9 February, 07:26

Duchenne muscular dystrophy is sex-linked and usually affects only males. Victims of the disease become progressively weaker, starting early in life.

a. What is the probability that a woman whose brother has Duchenne's disease will have an affected child?

b. If your mother's brother (your uncle) had Duchenne's disease, what is the probability that you have received the allele?

c. If your father's brother had the disease, what is the probability that you have received the allele?

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Answers (1)

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Nadia · Answer 1

1. Is the child is born male then the then the probability is 50%, and if female then the child will be normal provided father is normal.

2. Probability of me receiving the affected gene is 50%.

3. If the mother is normal then 0% chance that the child will receive mutated allele in his genome.

Explanation:

Duchenne muscular dystrophy is sex linked recessive disease which is seen as hereditary disease. This disease has a mutated gene which is present on the X chromosome. It produces proteins that results in muscular dystrophy.

A. As the mother's brother is affected with the disease so we can assume that the mother is a carrier of this disease. Hence one of the X chromosomes of mother is affected. If the child is female then 1 X chromosome will be received from father and other one from mother. So if the father is normal then even if the child receives mutated X chromosome from mother then also she will be normal. So a female child want to be a diseased one if the father is normal. If the child is male then and there is a 50% chance that the X chromosome he is receiving from mother is the mutated one. Show the chance of child being diseased is 50%.

B. As the mother's brother is deceased then the mother is taken to be a carrier. Hence one of the X chromosomes of mother is mutated and other one is normal. Hence the chance of receiving the mutated allele from mother is becomes 50%.

C. As the father's brother is having disease but father is not having the disease then fathers X chromosome must be normal because if the mutated allele was present then father would have been diseased as well. Hence is the mother is normal then the chance of the child being diseased becomes 0%.