Catalytic promiscuity in the RNA World may have aided the evolution of prebiotic metabolism
Fig 4
The types of replicators in the two dimensional space of enzymatic activities.
Coloured regions represent parts of the phenotypic trait-space which replicators are permitted to occupy by the trade-off constraints. The concave orange line represents a strong trade-off, while the convex blue line stands for a weak trade-off between enzymatic activities A and B. Specialists (replicators in the green areas) have only one significant enzymatic activity; generalists (red area) feature both activities. Replicators of very weak or no catalytic activity are parasites (black area). While the generalist-specialists continuum is gradual, we distinguish them by artificial boundaries defined by a threshold value m = 0.01 (represented by black lines).