Question

Study the pedigree chart of a certain family given above and select the correct conclusion which can be drawn for the character.

• A. The female parent is heterozygous.
• B. The parents could not have a normal daughter for this character.
• C. The trait under study could not be colour-blindness.
• D. The male parent is homozygous dominant.

Answer 1

The correct option is A The female parent is heterozygous.

To have affected progeny (affectd son and daughter) from affected male and normal female, the female should be heterozygous carrier of the trait. Since the trait is recessive, daughter can receive normal X chromosome for carrier mother and affected one from father. The resultant haterozygous daughter will be normal, though carrier. The trait under study may be colorblindness which is a X linked recessive disorder. The male parent is hemizygous recessive as human males carry one X chromosome (hemizygous) and the trait is recessive. Correct statement is A.