title: Biophysical mechanisms that maintain biodiversity through trade-offs.
abstract: Trade-offs are thought to arise from inevitable, biophysical limitations that prevent organisms from optimizing multiple traits simultaneously. A leading explanation for biodiversity maintenance is a theory that if the shape, or geometry, of a trade-off is right, then multiple species can coexist. Testing this theory, however, is difficult as trait data is usually too noisy to discern shape, or trade-offs necessary for the theory are not observed in vivo. To address this, we infer geometry directly from the biophysical mechanisms that cause trade-offs, deriving the geometry of two by studying nutrient uptake and metabolic properties common to all living cells. To test for their presence in vivo we isolated Escherichia coli mutants that vary in a nutrient transporter, LamB, and found evidence for both trade-offs. Consistent with data, population genetics models incorporating the trade-offs successfully predict the co-maintenance of three distinct genetic lineages, demonstrating that trade-off geometry can be deduced from fundamental principles of living cells and used to predict stable genetic polymorphisms.
authors.affiliation: Division of Biology, Section in Ecology, Behavior and Evolution, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Justin R
authors.initials: JR
authors.lastname: Meyer
authors.affiliation: Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Ivana
authors.initials: I
authors.lastname: Gudelj
authors.affiliation: Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Beardmore
mesh_terms: D044822:Biodiversity; D055592:Biophysical Phenomena; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D053858:Metabolic Networks and Pathways; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D017711:Nonlinear Dynamics; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism; D014312:Trisaccharides / Q000494:pharmacology
chemical_list: D014312:Trisaccharides; C008317:maltotriose