Achondroplasia is an autosomal dominant trait in humans that results in a form of dwarfism - VCE - SSCE Biology - Question 13 - 2006 - Paper 1
Question 13
Achondroplasia is an autosomal dominant trait in humans that results in a form of dwarfism. In some cases a child with achondroplasia is born to parents who have nor... show full transcript
Worked Solution & Example Answer:Achondroplasia is an autosomal dominant trait in humans that results in a form of dwarfism - VCE - SSCE Biology - Question 13 - 2006 - Paper 1
Step 1
A. the parents are carriers and the child has inherited the mutant allele from each parent.
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Answer
This statement is incorrect. If both parents had normal height, it is unlikely that they are carriers of the dominant trait.
Step 2
B. a mutation has occurred in a gamete of either the mother or the father.
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Answer
This is the most probable reason. In cases where both parents are of normal height, the mutation could have occurred in a gamete leading to the child inheriting the mutant allele.
Step 3
C. a mutation has occurred in a somatic cell of one of the parents.
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Answer
This statement does not apply. Somatic mutations typically do not get passed to offspring, as they do not affect the gametes.
Step 4
D. a mutation has occurred in the tissues of the child.
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This statement is also incorrect because the trait is inherited, not caused by a mutation occurring after conception.
