title: Characterization of species-specific repeats in 613 prokaryotic species.
abstract: Prokaryotes are in general believed to possess small, compactly organized genomes, with repetitive sequences forming only a small part of them. Nonetheless, many prokaryotic genomes in fact contain species-specific repeats (>85 bp long genomic sequences with less than 60% identity to other species) as we have previously demonstrated. However, it is not known at present how frequent such species-specific repeats are and what their functional roles in bacterial genomes may be. Therefore, we have conducted a comprehensive survey of prokaryotic species-specific repeats and characterized them to examine as to whether there are functional classes among different repeats or not and how they are mutually related to each other. Of the 613 distinct prokaryotic species analyzed, 97% were found to contain at least one species-specific repeats. It seems interesting to note that the species-specific repeats thus identified appear to be functionally variable in different genomes: in some genomes, they are mostly associated with duplicated protein-coding genes, whereas in some other genomes with rRNA and tRNA genes. Contrary to what may be expected, only one-fourth of the species-specific repeats were found to be associated with mobile genetic elements.
authors.affiliation: Department of Bioinformatics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia. triinu.koressaar@ut.ee
authors.forename: Triinu
authors.initials: T
authors.lastname: Koressaar
authors.forename: Maido
authors.initials: M
authors.lastname: Remm
mesh_terms: D001483:Base Sequence; D019295:Computational Biology / Q000379:methods*; D004269:DNA, Bacterial / Q000235:genetics*; D016680:Genome, Bacterial / Q000235:genetics*; D023281:Genomics; D008969:Molecular Sequence Data; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D013045:Species Specificity
chemical_list: D004269:DNA, Bacterial; D012335:RNA, Ribosomal; D012343:RNA, Transfer