The mode of inheritance of the trait shown in the pedigree is
A - VCE - SSCE Biology - Question 8 - 2011 - Paper 1
Question 8
The mode of inheritance of the trait shown in the pedigree is
A. X-linked recessive.
B. X-linked dominant.
C. autosomal recessive.
D. autosomal dominant.
Worked Solution & Example Answer:The mode of inheritance of the trait shown in the pedigree is
A - VCE - SSCE Biology - Question 8 - 2011 - Paper 1
Step 1
X-linked recessive
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Answer
To determine if a trait is X-linked recessive, examine if it primarily affects males and can skip generations. Affected males can only pass the trait to daughters.
Step 2
X-linked dominant
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Answer
For a trait to be X-linked dominant, it should appear in both males and females but usually affects females more severely. Affected males pass the trait to all their daughters.
Step 3
autosomal recessive
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Answer
In this mode, the trait can skip generations, and both males and females can be equally affected. An affected individual typically has unaffected parents.
Step 4
autosomal dominant
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Answer
For autosomal dominant traits, the trait cannot skip generations, and affected individuals will have affected parents. Both males and females are equally likely to be affected.
Step 5
Final Answer
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Answer
Based on the pedigree analysis, the correct mode of inheritance for the trait shown is D. autosomal dominant.
