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Research Article

Why Genes Evolve Faster on Secondary Chromosomes in Bacteria

  • Vaughn S. Cooper mail,

    vaughn.cooper@unh.edu

    Affiliation: Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, United States of America

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  • Samuel H. Vohr,

    Affiliation: Department of Computer Science, University of New Hampshire, Durham, New Hampshire, United States of America

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  • Sarah C. Wrocklage,

    Affiliation: Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, United States of America

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  • Philip J. Hatcher

    Affiliation: Department of Computer Science, University of New Hampshire, Durham, New Hampshire, United States of America

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  • Published: April 01, 2010
  • DOI: 10.1371/journal.pcbi.1000732

Reader Comments (3)

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Extending earlier findings in Burkholderia

Posted by vdenef on 02 Apr 2010 at 18:36 GMT

This paper further develops earlier observations reported by Chain et al. in 2006: http://www.pnas.org/conte....

No competing interests declared.

RE: Extending earlier findings in Burkholderia

vscooper replied to vdenef on 05 Apr 2010 at 19:10 GMT

It is correct to relate this paper to the Chain et al (2006) paper and also to many of the other "genome papers" of other bacteria with multiple chromosomes. We regret not formally considering and citing this fine paper. However, the major advance of our paper is that it presents a mechanism *why* secondary chromosomes in bacteria should always evolve more rapidly: the reduced gene dosage and thus reduced expression associated with delayed replication during the cell cycle. If correct, secondary chromosomes will always appear to be more evolutionarily malleable both in terms of rate and content, and thus variability on secondary chromosomes evolves more in the absence of purifying selection than in response to positive, niche-specific selection.

No competing interests declared.

RE: RE: Extending earlier findings in Burkholderia

vdenef replied to vscooper on 05 Apr 2010 at 23:04 GMT

It is indeed not feasible to refer back to all previous related observations, in particular when they were not the main focus of the paper. There is also no discussion that the current paper goes far beyond what has been previously reported. While I follow the gene dosage effect argument in case of rapid growth, I am not sure whether this is fully applicable to Burkholderia. As current thinking goes, Burkholderia, in particular when in their environmental (not host-associated) niche, do not rapidly reproduce.

No competing interests declared.