Environmental and genetic perturbations reveal different networks of metabolic regulation

Authors

Anthony J. Greenberg, Cornell University, IthacaFollow
Sean R. Hacket, Cornell University, Ithaca & Princeton University, Princeton
Lawrence G. Harshman, University of Nebraska - LincolnFollow
Andrew G. Clark, Cornell University, IthacaFollow

Date of this Version

2011

Citation

Molecular Systems Biology 7:563 doi:10.1038/msb.2011.96

Comments

2011 EMBO and Macmillan Publishers Limited

Abstract

Progress in systems biology depends on accurate descriptions of biological networks. Connections in a regulatory network are identified as correlations of gene expression across a set of environmental or genetic perturbations. To use this information to predict system behavior, we must test how the nature of perturbations affects topologies of networks they reveal. To probe this question, we focused on metabolism of Drosophila melanogaster. Our source of perturbations is a set of crosses among 92 wild-derived lines from five populations, replicated in a manner permitting separate assessment of the effects of genetic variation and environmental fluctuation. We directly assayed activities of enzymes and levels of metabolites. Using a multivariate Bayesian model, we estimated covariance among metabolic parameters and built fine-grained probabilistic models of network topology. The environmental and genetic co-regulation networks are substantially the same among five populations. However, genetic and environmental perturbations reveal qualitative differences in metabolic regulation, suggesting that environmental shifts, such as diet modifications, produce different systemic effects than genetic changes, even if the primary targets are the same.