Inheritance and Variation — BIOLOGY STD 12 Science — Question

Monohybrid cross

Dihybrid cross

1. Crosses involving a single pair of alleles are called monohybrid crosses.

1. Crosses involving two pairs of alleles are called dihybrid crosses.

2. Monohybrid crosses yield a phenotypic ratio of 3 : 1 in the F₂ generation.

2. Dihybrid crosses yield a 9 : 3 : 3 : 1 ratio in F₂ generation.

3. Monohybrid crosses yield 1 : 2 : 1 genotypic ratio in F₂ generation.

3. Dihybrid crosses yield 1 : 1 : 2 : 2 : 4 : 2 : 2 : 1 : 1 genotypic ratio in F₂ generation.

4. Application of the law of independent assortment is not applicable in monohybrid crosses.

4. Application of the law of independent assortment is applicable in dihybrid crosses.