Question

In a dihybrid cross AABB × aabb, F2 progeny of AABB, AABb, AaBB and AaBb occurs in ratio of________.

• A. 1: 1: 1: 1
• B. 9: 3: 3: 1
• C. 1: 2: 2: 1
• D. 1: 2: 2: 4

Answer 1

The correct option is D 1: 2: 2: 4

The punnett square chart for F2 generation is as follows:
$\begin{array}{ccccc}\text{Gametes}& \text{AB}& \text{aB}& \text{Ab}& \text{ab}\\ \text{AB}& \text{AABB}& \text{AaBB}& \text{AABb}& \text{AaBb}\\ \text{aB}& \text{AaBB}& \text{aaBB}& \text{AaBb}& \text{aaBb}\\ \text{Ab}& \text{AABb}& \text{AaBb}& \text{AAbb}& \text{Aabb}\\ \text{ab}& \text{AaBb}& \text{aaBb}& \text{Aabb}& \text{aabb}\end{array}$
Thus, the ratio of AABB, AABb, AaBB and AaBb is 1 : 2 : 2 : 4.