title: The chromosome copy number of the hyperthermophilic archaeon Thermococcus kodakarensis KOD1.
abstract: The euryarchaeon Thermococcus kodakarensis is a well-characterized anaerobic hyperthermophilic heterotroph and due to the availability of genetic engineering systems it has become one of the model organisms for studying Archaea. Despite this prominent role among the Euryarchaeota, no data about the ploidy level of this species is available. While polyploidy has been shown to exist in various Euryarchaeota, especially Halobacteria, the chromosome copy number of species belonging to one of the major orders within that phylum, i.e., the Thermococcales (including Thermococcus spp. and Pyrococcus spp.), has never been determined. This prompted us to investigate the chromosome copy number of T. kodakarensis. In this study, we demonstrate that T. kodakarensis is polyploid with a chromosome copy number that varies between 7 and 19 copies, depending on the growth phase. An apparent correlation between the presence of histones and polyploidy in Archaea is observed.
authors.affiliation: Laboratory of Microbiology, Wageningen University, PO Box 8033, 6700 EJ, Wageningen, The Netherlands, sebastiaan.spaans@wur.nl.
authors.forename: Sebastiaan K
authors.initials: SK
authors.lastname: Spaans
authors.forename: John
authors.initials: J
authors.lastname: van der Oost
authors.forename: Servé W M
authors.initials: SW
authors.lastname: Kengen
mesh_terms: D019847:Chromosomes, Archaeal / Q000235:genetics* / Q000378:metabolism; D019712:Thermococcus / Q000235:genetics* / Q000378:metabolism