title: Comparative study of three commonly used continuous deterministic methods for modeling gene regulation networks.
abstract: BACKGROUND
  A gene-regulatory network (GRN) refers to DNA segments that interact through their RNA and protein products and thereby govern the rates at which genes are transcribed. Creating accurate dynamic models of GRNs is gaining importance in biomedical research and development. To improve our understanding of continuous deterministic modeling methods employed to construct dynamic GRN models, we have carried out a comprehensive comparative study of three commonly used systems of ordinary differential equations: The S-system (SS), artificial neural networks (ANNs), and the general rate law of transcription (GRLOT) method. These were thoroughly evaluated in terms of their ability to replicate the reference models' regulatory structure and dynamic gene expression behavior under varying conditions.
  
  
  RESULTS
  While the ANN and GRLOT methods appeared to produce robust models even when the model parameters deviated considerably from those of the reference models, SS-based models exhibited a notable loss of performance even when the parameters of the reverse-engineered models corresponded closely to those of the reference models: this is due to the high number of power terms in the SS-method, and the manner in which they are combined. In cross-method reverse-engineering experiments the different characteristics, biases and idiosynchracies of the methods were revealed. Based on limited training data, with only one experimental condition, all methods produced dynamic models that were able to reproduce the training data accurately. However, an accurate reproduction of regulatory network features was only possible with training data originating from multiple experiments under varying conditions.
  
  
  CONCLUSIONS
  The studied GRN modeling methods produced dynamic GRN models exhibiting marked differences in their ability to replicate the reference models' structure and behavior. Our results suggest that care should be taking when a method is chosen for a particular application. In particular, reliance on only a single method might unduly bias the results.
authors.affiliation: University of Ulster, School of Biomedical Sciences, Cromore Road, Coleraine BT52 1SA, Co, Londonderry, UK.
authors.forename: Martin T
authors.initials: MT
authors.lastname: Swain
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: Mandel
authors.forename: Werner
authors.initials: W
authors.lastname: Dubitzky
mesh_terms: D019295:Computational Biology / Q000379:methods; D020869:Gene Expression Profiling / Q000379:methods*; D053263:Gene Regulatory Networks / Q000235:genetics*; D008957:Models, Genetic; D014158:Transcription, Genetic