Question

A blue-eyed woman and a brown-eyed heterozygous man are having a child. Blue is recessive to brown eyes in humans. What is the genotype ratio?

a) 1:0

b) 1:1

c) 1:2

d) 2:1

Answer 1

The genotype ratio for the offspring from a cross between a blue-eyed woman and a brown-eyed heterozygous man is 1:1, with half of the children expected to be brown-eyed (Bb) and the other half blue-eyed (bb). The correct option is b) 1:1

Step-by-step explanation:

The student is asking about the genotype ratio in the offspring from a cross between a blue-eyed woman (which must have the genotype bb, since blue is recessive) and a brown-eyed heterozygous man (with the genotype Bb, where B is the dominant allele for brown eyes). To figure out the genotype ratio for their children, we can use a Punnett square to predict the possible genotypes.

• If B represents the dominant brown-eye allele and b the recessive blue-eye allele, the woman's genotype is bb.
• The man is heterozygous for brown eyes, so his genotype is Bb.

By crossing these genotypes (Bb x bb), the potential offspring genotypes will be Bb (brown-eyed) and bb (blue-eyed).

The genotype ratio for their children would be 1:1, where 1 is brown-eyed (Bb) and 1 is blue-eyed (bb). The correct option is b) 1:1