CBSE 2023 · Region 1 · Set 2 · Q28 · 3 marks
Study the pedigree chart given below and answer the questions that follow:
(i)Is this trait recessive or dominant? Give reason.(ii)Is this trait sex-linked or autosomal ? Give reason.(iii)Among individuals $\displaystyle 3$, $\displaystyle 4$ and $\displaystyle 7$, which one is homozygous for the trait?
Study the pedigree chart given below and answer the questions that follow:
(i)
Is this trait recessive or dominant? Give reason.
(ii)
Is this trait sex-linked or autosomal ? Give reason.
(iii)
Among individuals $\displaystyle 3$, $\displaystyle 4$ and $\displaystyle 7$, which one is homozygous for the trait?
Marking-scheme solution
(i) •Recessive Trait
Individual $\displaystyle 3$ and $\displaystyle 4$ both do not suffer from the disease but have passed it to their
offspring individual no. $\displaystyle 7$/ Unaffected parents of individual $\displaystyle 7$ have transmitted the trait to him.(ii) •Autosomal
-Both the sexes have equal chance having the trait.
(iii) Individual $\displaystyle 7$ is - homozygous.
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CBSE Class 12 Biology past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.