Principles of Inheritance and Variation Question 96

96. In a cross between $AABB \times$ aabb, the ratio of $F_2$ genotypes between AABB, AaBB, Aabb and aabb would be

[1992]

(a) $9: 3: 3: 1$

(b) $2: 1: 1: 2$

(c) $1: 2: 2: 1$

(d) $7: 5: 3: 1$

Show Answer

Answer : c

Hints & Solution

(c) Genotype is the genetic make up of an individual irrespective of the Mendelian characters or genes impressing.

$AB$ $Ab$ $aB$ $ab$
$AB$ $AABB$ $AABb$ $AaBB$ $AaBb$
$Ab$ $AABb$ $AAbb$ $AaBb$ $Aabb$
$aB$ $AaBB$ $AaBb$ $aaBB$ $aaBb$
$ab$ $AaBb$ $Aabb$ $aaBb$ $aabb$