Question

Blue eye colour in human is recessive to brown eye colour. The expected children of a blue-eyed woman and a brown-eyed man who had a blue-eyed mother is likely to be in the ratio of:

• A. All blue-eyed
• B. Three blue-eyed and one brown-eyed
• C. All brown-eyed
• D. One blue-eyed and one brown-eyed

Answer 1

The correct option is D

One blue-eyed and one brown-eyed

The recessive character is expressed only in homozygous condition. Thus, blue-eyed woman will have 'bb' genotype, while brown-eyed man may have 'BB' or 'Bb' genotype. But the man had a blue-eyed mother, so, he will have 'Bb' genotype. It can be explained as follows: