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Open Access Highly Accessed Research article

Latent phenotypes pervade gene regulatory circuits

Joshua L Payne12 and Andreas Wagner123*

Author Affiliations

1 University of Zurich, Zurich, Switzerland

2 Swiss Institute of Bioinformatics, Lausanne, Switzerland

3 The Santa Fe Institute, Santa Fe, USA

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BMC Systems Biology 2014, 8:64  doi:10.1186/1752-0509-8-64

Published: 30 May 2014

Abstract

Background

Latent phenotypes are non-adaptive byproducts of adaptive phenotypes. They exist in biological systems as different as promiscuous enzymes and genome-scale metabolic reaction networks, and can give rise to evolutionary adaptations and innovations. We know little about their prevalence in the gene expression phenotypes of regulatory circuits, important sources of evolutionary innovations.

Results

Here, we study a space of more than sixteen million three-gene model regulatory circuits, where each circuit is represented by a genotype, and has one or more functions embodied in one or more gene expression phenotypes. We find that the majority of circuits with single functions have latent expression phenotypes. Moreover, the set of circuits with a given spectrum of functions has a repertoire of latent phenotypes that is much larger than that of any one circuit. Most of this latent repertoire can be easily accessed through a series of small genetic changes that preserve a circuit’s main functions. Both circuits and gene expression phenotypes that are robust to genetic change are associated with a greater number of latent phenotypes.

Conclusions

Our observations suggest that latent phenotypes are pervasive in regulatory circuits, and may thus be an important source of evolutionary adaptations and innovations involving gene regulation.

Keywords:
Exaptation; Genotype-phenotype map; Multifunctionality