Question

Assertion :Albinism in a man is controlled by recessive gene (a). If a normal pigmented man (Aa), a carrier, is crossed with albino female (aa) then 50% children will be albino. Reason: The ratio of albino and normal will be 1:2.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Both Assertion and Reason are incorrect.

Answer 1

The correct option is C Assertion is correct but Reason is incorrect.

Albinism is an autosomal recessive disorder which means that only homozygous recessive genotype will show the disorder. The heterozygous genotype will be normal but will serve as carrier since the recessive gene is masked by presence of normal dominant gene. According to the question, father is carrier and mother is albino.
Parent generation : aa (albino mother) x Aa (carrier father)

Gametes : aa Aa	a	a
A	Aa (normal carrier child)	Aa (normal carrier child)
a	aa (albino child)	aa (albino child)

F${}_1$ generation = 1 normal child: 1 albino. Hence, if a normal pigmented man (Aa), a carrier is crossed with albino female (aa) then 50% children will be albino; assertion is right. But the ratio of normal and albino children will be 1:1. The reason is wrong. Option C is the correct answer.