title: CRISPR elements in the Thermococcales: evidence for associated horizontal gene transfer in Pyrococcus furiosus.
abstract: The presence and distribution of CRISPR (clustered regularly interspaced short palindrome repeat) elements in the archaeal order Thermococcales were analyzed. Four complete genome sequences from the species Pyrococcus abyssi, P. furiosus, P. horikoshii, and Thermococcus kodakaraensis were studied. A fragment of the genome of P. furiosus was flanked by CRISPR elements upstream and by a single element downstream. The composition of the gene sequences contained in this genome fragment (positions 699013 to 855319) showed significant differences from the other genes in the P. furiosus genome. Differences were observed in the GC content at the third codon positions and the frequency of codon usage between the genes located in the analyzed fragment and the other genes in the P. furiosus genome. These results represent the first evidence suggesting that repeated CRISPR elements can be involved in horizontal gene transfer and genomic differentiation of hyperthermophilic Archaea.
authors.affiliation: Institute for Natural Resources and Agrobiology, IRNAS-CSIC, Sevilla, Spain.
authors.forename: M C
authors.initials: MC
authors.lastname: Portillo
authors.forename: J M
authors.initials: JM
authors.lastname: Gonzalez
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D019641:DNA, Archaeal / Q000737:chemistry / Q000235:genetics; D022761:Gene Transfer, Horizontal; D020745:Genome, Archaeal; D010802:Phylogeny; D043903:Pyrococcus abyssi / Q000235:genetics; D020027:Pyrococcus furiosus / Q000235:genetics*; D043902:Pyrococcus horikoshii / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D020086:Short Interspersed Nucleotide Elements; D013045:Species Specificity; D019709:Thermococcales / Q000235:genetics*; D019712:Thermococcus / Q000235:genetics
chemical_list: D003062:Codon; D019641:DNA, Archaeal