Evolution of bow-tie architectures in biology Journal Article

Author(s): Friedlander, Tamar; Mayo, Avraham E; Tlusty, Tsvi; Alon, Uri
Article Title: Evolution of bow-tie architectures in biology
Affiliation IST Austria
Abstract: Bow-tie or hourglass structure is a common architectural feature found in many biological systems. A bow-tie in a multi-layered structure occurs when intermediate layers have much fewer components than the input and output layers. Examples include metabolism where a handful of building blocks mediate between multiple input nutrients and multiple output biomass components, and signaling networks where information from numerous receptor types passes through a small set of signaling pathways to regulate multiple output genes. Little is known, however, about how bow-tie architectures evolve. Here, we address the evolution of bow-tie architectures using simulations of multi-layered systems evolving to fulfill a given input-output goal. We find that bow-ties spontaneously evolve when the information in the evolutionary goal can be compressed. Mathematically speaking, bow-ties evolve when the rank of the input-output matrix describing the evolutionary goal is deficient. The maximal compression possible (the rank of the goal) determines the size of the narrowest part of the network—that is the bow-tie. A further requirement is that a process is active to reduce the number of links in the network, such as product-rule mutations, otherwise a non-bow-tie solution is found in the evolutionary simulations. This offers a mechanism to understand a common architectural principle of biological systems, and a way to quantitate the effective rank of the goals under which they evolved.
Keywords: Signal Transduction; design principles; biological networks; evolutionary simulations; hourglass
Journal Title: PLoS Computational Biology
Volume: 11
Issue 3
ISSN: 1553-7358
Publisher: Public Library of Science  
Date Published: 2015-03-23
Start Page: Article number: e1004055
Copyright Statement: CC-BY
DOI: 10.1371/journal.pcbi.1004055
Notes: The research leading to these results received funding from the Israel Science Foundation and the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013) /ERC Grant agreement n° 249919. UA is the incumbent of the Abisch-Frenkel Professorial Chair. TF acknowledges partial funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013) under REA grant agreement n° 291734.
Open access: yes (OA journal)
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