Question

A normal woman whose father was albino, marries an albino man. What proportion of normal and albino are expected among their offspring?

• A. All normal
• B. 2 normal : 1 albino
• C. All albino
• D. 1 normal : 1 albino

Answer 1

The correct option is D 1 normal : 1 albino

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 of normal woman was albino (aa). Since the woman is normal, she would have received the affected allele from her father which is masked by presence of dominant allele (A) and she has normal phenotype but Aa genotype (carrier).
Parent generation : aa (albino man) x Aa (carrier woman)

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. Option D is the correct answer.