Core Genes Evolve Rapidly in the Long-term Evolution Experiment with Escherichia coli

Rohan Maddamsetti; Philip J Hatcher; Barry L. Williams; Richard E. Lenski

doi:10.1101/042069

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bioRxiv · 10.1101/042069

Core Genes Evolve Rapidly in the Long-term Evolution Experiment with Escherichia coli

Rohan Maddamsetti·Philip J Hatcher·Barry L. Williams·Richard E. Lenski

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Abstract

Bacteria can evolve rapidly under positive selection owing to their vast numbers, allowing their genes to diversify by adapting to different environments. We asked whether the same genes that are fast evolving in the long-term evolution experiment with Escherichia coli (LTEE) have also diversified extensively in nature. We identified ~2000 core genes shared among 60 E. coli strains. During the LTEE, core genes accumulated significantly more nonsynonymous mutations than flexible (i.e., noncore) genes. Furthermore, core genes under positive selection in the LTEE are more conserved in nature than the average core gene. In some cases, adaptive mutations appear to fine-tune protein functions, rather than merely knocking them out. The LTEE conditions are novel for E. coli, at least in relation to the long sweep of its evolution in nature. The constancy and simplicity of the environment likely favor the complete loss of some unused functions and the fine-tuning of others.\n\nCompeting Interests StatementWe, the authors, declare that we have no conflicts of interest.

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Rohan Maddamsetti, Philip J Hatcher, Barry L. Williams, Richard E. Lenski. 2016-03-01. Core Genes Evolve Rapidly in the Long-term Evolution Experiment with Escherichia coli. https://doi.org/10.1101/042069

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