Scale-free networks in evolution

In this paper we address the emergence of scale-free behavior in a simple evolutionary model. We model a growing population that starts from a small number of genotypes and then starts to grow due to an unlimited amount of available resources. These genotypes are subjected to the action of natural selection and mutation and increase in number according to their Malthusian rates. We show that the distribution of links for the genotypes is well described by a scale-free distribution. This is an evidence that combinatorial optimization processes can yield scale-free patterns. (C) 2003 Elsevier Science B.V. All rights reserved.