Question

Explain how is it possible for brown eyed parents to have a blue-eyed child. Which law does it illustrate? [5 MARKS]

Answer 1

Explanation: 2 Marks
Law: 1 Mark
Representation: 2 Marks

Brown eye colour is dominant over blue eye colour. Therefore, for the brown-eyed parents having blue-eyed child, the possibility is that both have heterozygous genotype i.e. Bb. Therefore, from the square below, it is clear that there is a 25% possibility of blue-eyed (bb) child. It illustrates the law of dominance which states that "out of a pair of contrasting characters brought together in an offspring, one always dominates over the other. The one that is expressed is dominant and the one that remains masked is recessive.