Figure 1.

Schematic diagram of potential patterns of hybrid gene expression. This hypothetical gene exhibits higher expression in parent 2 than in parent 1. Five different potential patterns of hybrid expression (A-E) are diagrammed. The hybrid could exhibit (A) below-low parent expression (BLP); (B) low parent-like expression (LP); (C) mid-parent expression; (D) high parent-like expression (HP); or (E) above high parent expression (AHP). Only mid-parent expression is classified as additive. The BLP, LP-like, HP-like and AHP expression patterns would all be examples of non-additive expression.