Fig. 2: Fitness landscapes for multiple functional parameters in response to induction with resveratrol.
From: Epistasis shapes the fitness landscape of an allosteric specificity switch
Fitness landscapes of (a) fold induction, (b) basal gene expression, (c) maximum gene expression, and (d) EC50 parameters for all 16 TtgR variants in response to resveratrol with each variant shown as a node in the graph. Each variant is labeled with a binary string corresponding to the presence (1) or absence (0) of a mutation at position 137, 141, 167, or 168 in order. Nodes separated by a single mutation are connected by edges showing viable (bold red) and unviable paths (light gray) through sequence space. Nodes are shaded by log10 of the fitness parameter at 250 μM resveratrol normalized to the fitness of wild-type TtgR. Number of epistatic subnetworks in the resveratrol (e) fold induction, (f) basal gene expression, (g) maximum gene expression, and (h) EC50 landscape determined by Bahadur expansion. Non-epistatic subnetworks (N) are shown in white, magnitude epistasis (M) in pink, sign epistasis (S) in light purple, and reciprocal sign epistasis (RS) in dark purple.
