Abstract:

Background & Aims: Natural selection and neutral selection are two parallel and independent theories on the biology evolution, both in terms of evolutionary ideas and methodology. However, whether these two theories are intrinsically linked or can be integrated into a same theory has remained as one of the big scientific questions in evolutionary biology science community. The path-dependent selection based on the idea of path theories of modern physics and economics might be potential to integrate natural selection and neutral selection.

Summary: Path-dependent selection assumes that mutations in nature are completely random and non-directional, but that, in some specific spatio-temporal environments, positive feedback effects with the environment lead to recursive effects of that mutation and hence to the formation of paths. The process of biological evolution will be a process of selection of path frequency rather than fitness enhancement and will be strongly dependent on the evolutionary paths experienced in its history; there will be acceleration or deceleration effects in the formation of paths due to the existence of transition probabilities between different evolutionary paths, explaining the discontinuity-equilibrium principle advocated by Gould et al. The theoretical model also implies that there might exist a link between natural selection and neutral selection based on an evolutionary game model, using the path integral form of the transition probability density function. When the environmental selection pressure is small or zero, most or all paths are equivalent; whereas, as the environmental pressure increases, the frequency of different paths will differentiate and paths with higher frequency are more likely to be selected. When environmental pressures are high and history or evolutionary processes have no effect on the evolution of the path itself (static, equilibrium state), the path with the highest frequency is the one that has taken the shortest time to evolve or is optimal—a result of Darwin’s theory of natural selection.

Prospects: Path-dependent selection based on path-integral methods used in modern physics, especially quantum mechanics, may provide us with a different perspective and approach to explaining the evolution of life. In existing theoretical models of pathway evolution, transition probabilities are continuously distributed, and the trajectories on which these transition probabilities themselves occur are paths. However, in the evolution of life, transition probabilities like the plasmid transfer or transposons, are intermittently discontinuous across paths. The mathematical structure of these problems in the life sciences will place new demands on physics and mathematical methods, and will likely provide new ideas for new developments in physics.

Key words: path dependence, natural selection, neutral selection, Lamarckism, punctuated equilibrium