Plastic tradeoffs in evolution: a simple theoretical model

Performance tradeoffs are fundamental to evolutionary thinking, but in most models, are simply postulated. This approach is justified for tradeoffs enforced by rigid biophysical or biochemical constraints; unsurprisingly, the best-understood examples are in this class. However, experimental results suggest that many relevant tradeoffs are not rigid, but can themselves evolve. We propose a simple theoretical framework for studying how an evolving tradeoff structure both shapes and is shaped by the evolutionary trajectory. We show that this feedback loop naturally leads to non-intuitive behaviors. For instance, although strongly diverging tasks might be expected to result in stronger tradeoffs, evolution can reverse this trend. We also show that within our model, pre-evolving a genome in one environment can predictably impede or facilitate its subsequent speed of adaptation in another. Our results extend previous work relating modularity and “evolvability” to a more general discussion of flexible tradeoff architectures and their impact on evolutionary dynamics.