Probability models for degree distributions of protein interaction networksM. P. H. Stumpf and P. J. Ingram
Centre for Bioinformatics, Department of Biological Sciences Imperial College London - SW7 2AZ, London, UK
received 22 October 2004; accepted in final form 3 May 2005
published online 1 June 2005
The degree distribution of many biological and technological networks has been described as a power-law distribution. While the degree distribution does not capture all aspects of a network, it has often been suggested that its functional form contains important clues as to underlying evolutionary processes that have shaped the network. Generally, the functional form for the degree distribution has been determined in an ad hoc fashion, with clear power-law-like behaviour often only extending over a limited range of connectivities. Here we apply formal model selection techniques to decide which probability distribution best describes the degree distributions of protein interaction networks. Contrary to previous studies, this well-defined approach suggests that the degree distribution of many molecular networks is often better described by distributions other than the popular power-law distribution. This, in turn, suggests that simple, if elegant, models may not necessarily help in the quantitative understanding of complex biological processes.
89.75.Fb - Structures and organization in complex systems.
02.50.Tt - Inference methods.
87.16.Ac - Subcellular structure and processes. Theory and modelling; computer simulation.
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