Question: In pea plants there are three genes involved in growth. One gene involves maternal effect and determines initial growth rate, with the T allele allowing for tall plants and t resulting in short plants.The other two genes are expressed in the nucleus and override the “shortness” effect of t in the egg. Dominance in both (A_ B_) results in tall plants. Recessive alleles in one of the two genes (aa B_
or A_ bb) results in plants with medium height, and recessive individuals (aabb) are short. These genes have no effect on the T allele.

a) If a TtAABB plant is crossed with a Ttaabb plant, what would the phenotypic and corresponding genotypic ratios be in their offspring? Show clearly the contribution from the female’s eggs.

b) Draw a pathway for the inheritance of height in pea plants.

c) If the F1 are then crossed what will the phenotypic ratio be in the F2? Show clearly the contribution from the F1 female’s eggs