CBSE 2023 · Region 1 · Set 1 · Q23 · 3 marks
Study the given pedigree chart and answer the questions that follow.
(a)Is the trait given in the chart dominant or recessive ? Give reason in support of your answer.(b)Is this trait autosomal or sex-linked ? Give reason in support of your answer.(c)Write the possible genotypes of the children numbers '$\displaystyle 1$' and '$\displaystyle 3$' of the second generation.
Study the given pedigree chart and answer the questions that follow.
(a)
Is the trait given in the chart dominant or recessive ? Give reason in support of your answer.
(b)
Is this trait autosomal or sex-linked ? Give reason in support of your answer.
(c)
Write the possible genotypes of the children numbers '$\displaystyle 1$' and '$\displaystyle 3$' of the second generation.
Marking-scheme solution
(a)
Recessive trait, both the parents in generation I do not express the trait yet it appears in the progeny.
(b) Autosomal trait, both male and females have equal chances of getting the trait.
(c) Child '$\displaystyle 1$' : Aa/AA, Child '$\displaystyle 3$' : Aa
//
(a) Recessive trait, both the parents in generation I do not express the trait, yet it appears in the progeny.
(b) Sex linked trait, comparatively more male are getting affected.
(c) Child '$\displaystyle 1$' : XY, Child '$\displaystyle 3$': X' X(carrier)
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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.