Blue eyes are recessive to brown. A brown eyed man marries a blue-eyed woman. What are the possible phenotypes and genotypes of their potential children? How many could have blue eyes?
Trait: Eye colour
Brown-eyed man has the following genotype: BB( homozygous dominant) and the gametes are- B, B
Blue-eyed woman has the following genotype: bb(homozygous recessive) and the gametes are- b,b
A cross between the two persons will yield the following result shown with the help of Punnett square.
b | b | |
B | Bb | Bb |
B | Bb | Bb |
From the Punnett square, we can see that all offsprings( heterogeneous dominant) exhibit brown eye colour as the dominant gene B is present in all cases.
Hence, the phenotypic ratio- all alike
And, as the genes present in each individual is the same, thus the genotypic ratio will be all alike.
None of the offsprings will exhibit blue coloured eyes.
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