B2.7.2. NK fitness landscapes

NK fitness landscapes are stochastically generated fitness functions on bit strings, parameterized (with N genes and K interactions between genes) so as to make them tunably ‘rugged’. Under the ‘natural ’ genetic operators of bit-flipping mutation or recombination, NK landscapes produce multiple domains of attrac-tion for the evolutionary dynamics. NK landscapes have been used in models of epistatic gene interactions, coevolution, genome growth, and Wright’s shifting bal-ance model of adaptation. Theory for adaptive walks on NK landscapes has been derived, and generalizations that extend beyond Kauffman’s original framework have been utilized in these applications. Keywords: adaptive landscape, adaptive walk, coevolution, computational complexity, ‘edge of chaos’, epistasis, ‘House of Cards ’ model, multiple domains of attraction, pleiotropy, random field, random number generators, ‘Red Queen ’ Hypothesis, representation problem, self-organized criticality, shifting-balance model, spin glas