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Large variations in bacterial ribosomal RNA genes
Kyungtaek Lim1, Yoshikazu Furuta, Ichizo Kobayashi
1Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, Minato-ku, Tokyo, Japan.
Molecular Biology and Evolution
|March 27, 2012
Summary
Bacterial ribosomal RNA (rRNA) genes show surprising variations, including the loss of the anti-Shine-Dalgarno sequence. These evolutionary changes impact gene arrangement and function, revealing dynamic shifts in essential cellular machinery.
Area of Science:
- Microbiology
- Molecular Biology
- Evolutionary Biology
Background:
- Ribosomal RNA (rRNA) genes are fundamental to life and typically considered highly conserved.
- Limited knowledge exists regarding the natural variations and evolutionary dynamics of rRNA genes.
Purpose of the Study:
- To investigate large-scale variations in bacterial rRNA genes using bioinformatic analyses.
- To understand the formation mechanisms and biological significance of observed rRNA gene variations.
Main Methods:
- Bioinformatic analysis of complete bacterial genomic sequences.
- Reconstruction of rRNA gene rearrangement histories.
- Inference of evolutionary mechanisms and biological significance.
Main Results:
- Identified bacterial genomes lacking the conserved anti-Shine-Dalgarno sequence in 16S rRNA genes.
- Observed the co-occurrence of this loss with the elimination of Shine-Dalgarno-like sequences in protein-coding genes.
- Documented numerous rearranged rRNA genes, including inversions, duplications, deletions, and substitutions, with inferred biological significance.
Conclusions:
- Bacterial rRNA genes exhibit significant evolutionary plasticity beyond simple conservation.
- Variations in rRNA genes, including loss of key sequences and rearrangements, are linked to functional and evolutionary advantages.
- These findings provide insights into the dynamic evolution of rRNA genes and the bacterial translational machinery.
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