To understand the conditions under which mutations and selection can lead to rising level of organization is of importance for evolutionary biology as well as in evolutionary computations. The fundamental dynamical processes of evolution are connected to processes based on sequences. Nature apparently explores some unknown mechanisms of strings nets complexification. I intend to overview here some findings on the way of searching and exploitation of the algorithms for the complexification. I think these algorithms could find applications in the presentation problem of evolutionary computations.
Considering detaily evolutionary pathways, we can discover stages of the emergence of novel features as well as stages of slow-scale change of existing ones. Gradual evolution after the emergence of a novel feature is often studied analytically, while the origin of features is analytically insoluble problem. For such problems, we require a mechanism for how complex, higher-level behavior emerges from low-level interactions, without the implementation of explicit rules for such emergence (Kaneko, 1994, Chaos as source of complexity and diversity in evolution, ALife, 1, 163-177).
According to classic point of view evolutionary complexification of the living beings apparently requires the co-ordinate change of several phenotypic characters to produce adaptive variants. However this requires simultaneous mutations at several genes. Of course, it is impossible!
On the other hand, genetic changes are not directly manifested in phenotypic changes. Rather, a complex developmental machinery mediates between genetic information and phenotypic characteristics. It provides a certain robustness by filtering out genetic changes. Some genetic changes make little or no difference to the final phenotype. In other words, robustness is a way to escape the requirement of simultaneous mutations at several genes for evolutionary complexification.
Such degree of freedom allows the species to accumulate appropriate mutations without interruption of the development. When the volume of heritable changes achieving critical threshold, this can force out the development to a new higher-level trajectory.
See also
Evolution of Gene Networks by Andreas Wagner
Adaptation and Evolvability by Wagner & Altenberg
CANALIZATION OF FITNESS COMPONENTS by S. C. Stearns and T. J. Kawecki
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