Presentation Type

Poster

Abstract

In simple, constant environments containing one food source, theory and intuition suggest that only one type of organism should prevail. However, a lab population of E. coli founded by a single clone quickly evolved into a community of interacting cell types. Bacteria were cultured under glucose limitation, selecting for its avid consumption. One strain, A, best scavenges glucose but does so wastefully, providing strains B and C with by-products that support their growth. Thus, multiple interacting cell types may better use limited resources than one. I therefore posed the questions: How much more fit is each strain relative to the common ancestor, and does cohabitation provide fitness advantages? We competed strains of P, A, B, and C expressing green fluorescent proteins, and quantified their relative numbers in a simple, controlled environment. Fitnesses ranked as (A+B+C)>(A=B)>A>B>C, support the view that a cooperating community can evolve outperform a single individual. Quantifying relative fitness in experimentally evolved communities reveals that the sum may be greater than its parts, providing a clue as to how biocomplexity arises, even in simple systems governed by Darwinian principles.

Category

Life Sciences

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Apr 15th, 11:00 AM Apr 15th, 12:00 PM

Better than Before and Better Together

In simple, constant environments containing one food source, theory and intuition suggest that only one type of organism should prevail. However, a lab population of E. coli founded by a single clone quickly evolved into a community of interacting cell types. Bacteria were cultured under glucose limitation, selecting for its avid consumption. One strain, A, best scavenges glucose but does so wastefully, providing strains B and C with by-products that support their growth. Thus, multiple interacting cell types may better use limited resources than one. I therefore posed the questions: How much more fit is each strain relative to the common ancestor, and does cohabitation provide fitness advantages? We competed strains of P, A, B, and C expressing green fluorescent proteins, and quantified their relative numbers in a simple, controlled environment. Fitnesses ranked as (A+B+C)>(A=B)>A>B>C, support the view that a cooperating community can evolve outperform a single individual. Quantifying relative fitness in experimentally evolved communities reveals that the sum may be greater than its parts, providing a clue as to how biocomplexity arises, even in simple systems governed by Darwinian principles.