Assume that plant height is determined by a pair of alleles at each of two loci (A and a, B and b) that are additive in their effects. Further assume that each allele represented by an uppercase letter contributes 6 feet to height and that each allele represented by a lowercase letter contributes 2 foot to height. If a plant with genotype AaBB is crossed to a plant with genotype aaBb, what heights are expected in the progeny

16 feet, 20 feet, and 12 feet

Explanation:

Uppercase allele = 6 feet

Lowercase allele = 2 feet

First, let us look at the outcome of the cross between AaBB and aaBb.

      AaBB     x     aaBb

Progeny:

4 AaBB = 6+2+6+6 = 20 feet

4 aaBB = 2+2+6+6 = 16 feet

4 AaBb = 6+2+6+2 = 16 feet

4 aaBb = 2+2+6+2 = 12 feet

The heights expected in the progeny are 16 feet, 20 feet, and 12 feet.

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