Figure 4

A schematic depiction of our method for picking random, strict, pure, epistatic penetrance functions. Points in the parameter space, ${ℝ}^{2^n}$ correspond to pre-penetrance functions, and points in the shaded region correspond to strict, pure, epistatic penetrance functions. The vector $\overrightarrow{V}$ indicates a random direction in the set of pre-penetrance functions. $\overrightarrow{V}$ determines a random class of penetrance functions, which is indicated by the line in the shaded region. The point A on the boundary of this region indicates one (of the two) penetrance functions in this class with maximum heritability. The point B indicates the penetrance function in this class having specified values of prevalence and heritability (if one exists). It may be viewed as random among all those with these values.