Contributed talk in Evolution 2, Aug. 2, 2019, noon in room USB.2.022

Acclivation of Virtual Fitness Landscapes

Ben Kovitz, David Bender, Marcela Poffald

watch Publication Any part of a genome, considered separately from the rest of the genome, evolves against a ``virtual fitness landscape'' that results when the rest of the genome is held constant. We show that each part of a genome is under selective pressure to provide the other parts with a virtual fitness landscape that maximizes the evolvability of the other parts. When one part of a genome is a vector of numbers (``knobs''), and the rest is a graph that determines the mapping from knobs to phenotype, the graph is under selective pressure to acclivate the virtual fitness function faced by the knobs---that is, to make it more hill-shaped. When there is an evolutionary path for the graph to respond to this pressure, a synergy develops between the incremental exploration of phenotypes by knob-mutations and the discontinuous exploration by graph-mutations. This kind of genome exploits epistasis and non-locality of genotype--phenotype mapping to provide a mechanism by which organisms can evolve improved evolvability, especially against fitness functions that vary periodically while keeping some invariants unchanged. The graph accumulates a memory of the regions of the fitness landscape visited in previous generations, held in the form of bias limiting and directing future evolution.