Change in mean population fitness () under three models of Dominance of Fitness

Dominance, Additive, and Recessive models proceed as in SR2019 4.1. The three curves show the mean population fitness () for the three models, as f(A₁) 1.

The slope of the fitness curve is always positive, however the first derivative (d W/d p) shows how the change in the slope varies as f(A₁) 1. In the dominance model, the slope is initially rapid and then decreases. In the additive model, slope is constant.  In the recessive model, the slope is initially slow and then increases. The consequence of the contrast is seen in SR2019 4.3.

HOMEWORK: Observe that the dominant and recessive curves have the same shape, that is, if the green curve is flipped across the red curve, and flipped again along its length? Why is this ?