An End to Endless Forms: Epistasis, Phenotype Distribution Bias, and Nonuniform Evolution
The phenotypic dimension is set to k = 18. All curves represent the average of 1,000 different developmental matrices. (A) The number of potential phenotypes (2 r ) and the number of distinct visible phenotypes as a function of the regulatory dimension. (B) The percentage of visible phenotypes out of the potential phenotypes, corresponding to a sigmoidal function. (C) The marginal contribution of each genetic element to the increase in the number of visible phenotypes. Formally, if V(r) denotes the number of visible phenotypes as a function of r, then the marginal contribution is defined as V(r)/V(r−1), and is evidently linear (with slope of −0.044; least squares regression).