Question

Assertion (A): In humans, if gene b gives blue eyes and gene B gives brown eyes, then the colour of the eyes of a person having Bb combination of genes will be blue.

Reason (R): The recessive gene cannot show its effect in the presence of dominant gene.

Options

• Both A and R are true and R is correct explanation of the assertion.

• Both A and R are true but R is not the correct explanation of the assertion.

• A is true but R is false.

• A is false but R is true.

Answer 1

A is false but R is true.

Explanation:

In this case, B is the dominant gene for brown eyes, while b is the recessive gene for blue eyes. A person with the genotype Bb will have brown eyes because the dominant allele B masks the effect of the recessive allele b. Therefore, Assertion (A) is false.

A recessive gene cannot express its trait in the presence of a dominant gene because its effect is masked by the dominant allele. Therefore, Reason (R) is true.

Hence, A is false but R is true.