With independent assortment, the ratio of genotypes in the F₂ generation of a cross between true-breeding strains (AA bb × aa BB) can be described as 1:2:1:2:4:2:1:2:1. To what genotype does the "4" in the ratio refer? A)AA Bb B)Aa BB C)Aa Bb D)None of the answer options is correct.

Question

Quizplus · Accepted Answer

The "4" in the ratio refers to the genotype Aa Bb. This is the result of independent assortment of the two sets of alleles, with each having a 1/2 chance of being in the gamete. Therefore, the A and a alleles can be combined with equal probabilities to form the gametes, as can the B and b alleles. The genotype Aa Bb is produced when an Aa gamete combines with a Bb gamete, which occurs 4 times out of the total of 16 possible combinations in the F1 generation.

With Independent Assortment, the Ratio of Genotypes in the F2

With Independent Assortment, the Ratio of Genotypes in the F₂