  Recently it has been shown that a large variety of different networks have
power-law (scale-free) distributions of connectivities. We investigate the
robustness of such a distribution in discrete threshold networks under neutral
evolution. The guiding principle for this is robustness in the resulting
phenotype. The numerical results show that a power-law distribution is not
stable under such an evolution, and the network approaches a homogeneous form
where the overall distribution of connectivities is given by a Poisson
distribution.
