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Erosion of interaction networks in reduced and degraded genomes
Author(s) -
Ochman Howard,
Liu Renyi,
Rocha Eduardo P.C.
Publication year - 2007
Publication title -
journal of experimental zoology part b: molecular and developmental evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 63
eISSN - 1552-5015
pISSN - 1552-5007
DOI - 10.1002/jez.b.21147
Subject(s) - biology , genome , gene , horizontal gene transfer , lineage (genetic) , gene duplication , genetics , gammaproteobacteria , bacterial genome size , evolutionary biology , computational biology , 16s ribosomal rna
Unlike eukaryotes, which often recruit duplicated genes into existing protein–protein interaction (PPI) networks, the low levels of gene duplication coupled with the high probability of lateral transfer of novel genes alters the manner in which PPI networks can evolve in bacteria. By inferring the PPIs present in the ancestor to contemporary Gammaproteobacteria , we were able to trace the changes in gene repertoires, and their consequences on PPI network evolution, in several bacterial lineages that have independently undergone reductions in genome size and genome contents. As genomes degrade, virtually all multi‐partner proteins have lost interactors; however, the overall average number of connections increases due to the preferential elimination of proteins that interact with only one other protein partner. We also studied the effect of lateral gene transfer on PPI network evolution by analyzing the connectivity of genes that have been gained along the Escherichia coli lineage, as well as those acquired genes subsequently silenced in Shigella flexneri , since diverging from the gammaproteobacterial ancestor. The situation in PPI networks, in which newly acquired genes preferentially attach to the hubs of the network, contrasts that observed in metabolic networks, which evolve by the peripheral gain and loss of genes, and in regulatory networks, in which high connectivity increases the propensity of loss. J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007 . © 2007 Wiley‐Liss, Inc.