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Title: Does fitness in long-term evolution increase without limit?
Plain: In an experiment running since 1988, twelve populations of E. coli have kept getting fitter for more than 70,000 generations. Whether their fitness approaches a ceiling or rises forever is open.
Precise: For the E. coli long-term evolution experiment (12 populations in constant glucose-limited medium), relative fitness $w(t)$ up to 50,000 generations was fit better by a power law $w = (1 + b t)^a$ (unbounded) than by a hyperbola $w = 1 + c t/(t + d)$ (bounded) (Wiser, Ribeck and Lenski, 2013). Decide from later data whether $w(t)$ is bounded, and derive the trajectory from clonal-interference theory with diminishing-returns epistasis.
Settled by: Fitness assays across the full archive of frozen samples, with model comparison between bounded and unbounded forms.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: (empty)
Posed since: 2013