Large Variations in Bacterial Ribosomal RNA Genes
نویسندگان
چکیده
Ribosomal RNA (rRNA) genes, essential to all forms of life, have been viewed as highly conserved and evolutionarily stable, partly because very little is known about their natural variations. Here, we explored large-scale variations of rRNA genes through bioinformatic analyses of available complete bacterial genomic sequences with an emphasis on formation mechanisms and biological significance. Interestingly, we found bacterial genomes in which no 16S rRNA genes harbor the conserved core of the anti-Shine-Dalgarno sequence (5'-CCTCC-3'). This loss was accompanied by elimination of Shine-Dalgarno-like sequences upstream of their protein-coding genes. Those genomes belong to 1 or 2 of the following categories: primary symbionts, hemotropic Mycoplasma, and Flavobacteria. We also found many rearranged rRNA genes and reconstructed their history. Conjecturing the underlying mechanisms, such as inversion, partial duplication, transposon insertion, deletion, and substitution, we were able to infer their biological significance, such as co-orientation of rRNA transcription and chromosomal replication, lateral transfer of rRNA gene segments, and spread of rRNA genes with an apparent structural defect through gene conversion. These results open the way to understanding dynamic evolutionary changes of rRNA genes and the translational machinery.
منابع مشابه
Transcriptome Sequencing of Guilan Native Cow in Comparison with bosTau4 Reference Genome
RNA-sequencing is a new method of transcriptome characterization of organisms. Based on identity and relatedness, there are large genetic variations among different cattle breeds. The goal of the current study was to sequence the transcriptome of Guilan native cow and compare with available reference genome using RNA-sequencing method. Blood samples were collected from 14 Guilan native cows and...
متن کاملA comparative phylogenetic analysis of Theileria spp. by using two two "18S ribosomal RNA" and "Theileria annulata merozoite surface antigen" gene sequences
More than 185 species, strains and unclassified Theileria parasites are categorized in the Entrez Taxonomy. The accurate diagnosis and proper identification of the causative agents are important for understanding the epidemiology, prevention and appropriate treatment. This study aims to discuss the importance of two genes of Theileria annulata 18S ribosomal RNA (18S rRNA) and Theileria annulata...
متن کاملRNAmmer: consistent and rapid annotation of ribosomal RNA genes
The publication of a complete genome sequence is usually accompanied by annotations of its genes. In contrast to protein coding genes, genes for ribosomal RNA (rRNA) are often poorly or inconsistently annotated. This makes comparative studies based on rRNA genes difficult. We have therefore created computational predictors for the major rRNA species from all kingdoms of life and compiled them i...
متن کاملPhylogeny-function analysis of (meta)genomic libraries: screening for expression of ribosomal RNA genes by large-insert library fluorescent in situ hybridization (LIL-FISH).
We assessed the utility of fluorescent in situ hybridization (FISH) in the screening of clone libraries of (meta)genomic or environmental DNA for the presence and expression of bacterial ribosomal RNA (rRNA) genes. To establish proof-of-principle, we constructed a fosmid-based library in Escherichia coli of large-sized genomic DNA fragments of the mycophagous soil bacterium Collimonas fungivora...
متن کاملIntragenomic heterogeneity between multiple 16S ribosomal RNA operons in sequenced bacterial genomes.
The availability of a large number of completely sequenced bacterial genomes allows the rapid and reliable determination of intragenomic sequence heterogeneity of 16S rRNA genes. In the present study we assessed the intragenomic sequence heterogeneity of 16S rRNA genes in 55 bacterial genomes, representing various phylogenetic groups. The total number of rRNA operons in genomes included ranged ...
متن کامل