Duchenne muscular dystrophy is a sex-linked recessive genetic disorder caused by a mutation on a single gene on the X-chromosome - Edexcel - GCSE Biology - Question 5 - 2016 - Paper 1
Question 5
Duchenne muscular dystrophy is a sex-linked recessive genetic disorder caused by a mutation on a single gene on the X-chromosome.
The letter D can be used for the d... show full transcript
Worked Solution & Example Answer:Duchenne muscular dystrophy is a sex-linked recessive genetic disorder caused by a mutation on a single gene on the X-chromosome - Edexcel - GCSE Biology - Question 5 - 2016 - Paper 1
Step 1
What is the percentage chance of any child from person A inheriting the mutated allele?
96%
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Answer
The percentage chance of any child from person A inheriting the mutated allele is 0%. This is because person A does not carry the mutated allele, thus cannot pass it to their offspring.
Step 2
Explain the conclusion that can be made about the genotype of person C.
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Answer
Person C must be a carrier of the Duchenne muscular dystrophy allele (genotype XdX). This conclusion is drawn from the fact that person C has male offspring, one of whom has the disorder, indicating that person C must possess the mutated allele to pass it onto their child.
