title: Metabolic modeling of endosymbiont genome reduction on a temporal scale.
abstract: A fundamental challenge in Systems Biology is whether a cell-scale metabolic model can predict patterns of genome evolution by realistically accounting for associated biochemical constraints. Here, we study the order in which genes are lost in an in silico evolutionary process, leading from the metabolic network of Escherichia coli to that of the endosymbiont Buchnera aphidicola. We examine how this order correlates with the order by which the genes were actually lost, as estimated from a phylogenetic reconstruction. By optimizing this correlation across the space of potential growth and biomass conditions, we compute an upper bound estimate on the model's prediction accuracy (R=0.54). The model's network-based predictive ability outperforms predictions obtained using genomic features of individual genes, reflecting the effect of selection imposed by metabolic stoichiometric constraints. Thus, while the timing of gene loss might be expected to be a completely stochastic evolutionary process, remarkably, we find that metabolic considerations, on their own, make a marked 40% contribution to determining when such losses occur.
authors: The Blavatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel. kerenyiz@post.tau.ac.il
authors: Keren
authors: K
authors: Yizhak
authors: Tamir
authors: T
authors: Tuller
authors: Balázs
authors: B
authors: Papp
authors: Eytan
authors: E
authors: Ruppin
mesh_terms: D000818:Animals; D001042:Aphids / Q000382:microbiology; D005075:Biological Evolution; D020635:Buchnera / Q000235:genetics* / Q000378:metabolism; D003198:Computer Simulation; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D016680:Genome, Bacterial; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D008954:Models, Biological; D010802:Phylogeny; D012641:Selection, Genetic; D013559:Symbiosis / Q000235:genetics*; D049490:Systems Biology / Q000379:methods; D013997:Time Factors
chemical_list: D004269:DNA, Bacterial