Question

In the pedigree chart given below, what should be the genotype of the indicated member?

• A. AA
• B. Aa
• C. XY
• D. aa

Hint:

In autosomal dominant traits, affected individuals are typically heterozygous (Aa), and the trait appears in every generation, affecting both sexes.

Answer 1

The Correct Option is B

The pedigree shows an autosomal dominant trait (affected individuals in every generation, both sexes affected). The affected male parent is heterozygous (Aa), and the unaffected female parent is aa. The indicated female child is affected, so she must have inherited the dominant A allele from the father, making her genotype Aa. Option (A) AA is not possible as the mother is aa, (C) XY refers to sex chromosomes, not the trait, and (D) aa would mean she’s unaffected, which she isn’t.