Question

Analyze the results of a cross between two organisms that are both heterozygous for two

different genes (AaBb). Use a Punnett square to evaluate the possible genotypes (1) List all
the genotypes from your Punnett Square in the answer space (2) Determine how many
phenotypes can be produced in the offspring (3) Determine the probability of producing
offspring with the aabb genotype.

Answer 1

AB Ab aB ab

AB AABB AABb AaBB AaBb

Ab AABb AAbb AaBb Aabb

aB AaBB AaBb aaBB aaBb

ab AaBb Aabb aaBb aabb

Answer No 1:

A punnet square is a diagram which depicts the outcomes of a crosss. The punnet square for the cross between both heterozygous parents has been shown above. According to the punnet square, we can see that the possible genotypes are:

AABB, AABb, AaBB, AaBb, AAbb, Aabb,aaBB, aaBb, Aabb, aaBb and aabb.

Answer No 2:

The phenotypes produced in the offsprings will be of 4 types. Most probably the phenotypes will be in the ration 4:3:3:1.

As the punnet square shows, the phenoype AABB will be shown in a ratio of 4 out of 16. The phenotypes for aabb will be shown one out of 16.

Answer No 3:

As we can see through the punnet square, probability of aabb is 1 out of 16 which makes almost 6%.