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Genome Biology and Evolution


Genomes are dynamic in lineages across the tree of life. Among bacteria and archaea, for example, DNA content varies through out life cycles, and nonbinary cell division in diverse lineages indicates the need for coordination of the inheritance of genomes. These observations contrast with the textbook view that bacterial and archaeal genomes are monoploid (i.e., single copied) and fixed both within species and throughout an individual's lifetime. Here, we synthesize information on three aspects of dynamic genomes from exemplars representing a diverse array of bacterial and archaeal lineages: 1) ploidy level variation, 2) epigenetic mechanisms, and 3) life cycle variation. For example, the Euryarchaeota analyzed to date are all polyploid, as is the bacterium Epulopiscium that contains up to tens of thousands of copies of its genome and reproduces by viviparity. The bacterium Deinococcus radiodurans and the archaeon Halobacterium sp. NRC-1 can repair a highly fragmented genome within a few hours. Moreover, bacterial genera such as Dermocarpella and Planctomyces reproduce by fission (i.e., generating many cells from one cell) and budding, respectively, highlighting the need for regulation of genome inheritance in these lineages. Combining these data with our previous work on widespread genome dynamics among eukaryotes, we hypothesize that dynamic genomes are a rule rather than the exception across the tree of life. Further, we speculate that all domains may have the ability to distinguish germline from somatic DNA and that this ability may have been present the last universal common ancestor.


Epigenetics, Genome, Life cycle variation, LUCA, Polyploidy





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Creative Commons License

Creative Commons Attribution-Noncommercial 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 3.0 License


© The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited.


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