The birth of a bacterial tRNA gene by large-scale, tandem duplication events.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33124983.
- Also identified by DOI 10.7554/eLife.57947 and PMC identifier 7661048.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Organisms differ in the types and numbers of tRNA genes that they carry. While the evolutionary mechanisms behind tRNA gene set evolution have been investigated theoretically and computationally, direct observations of tRNA gene set evolution remain rare. Here, we report the evolution of a tRNA gene set in laboratory populations of the bacterium <i>Pseudomonas fluorescens</i> SBW25. The growth defect caused by deleting the single-copy tRNA gene, <i>serCGA</i>, is rapidly compensated by large-scale (45-290 kb) duplications in the chromosome. Each duplication encompasses a second, compensatory tRNA gene (<i>serTGA</i>) and is associated with a rise in tRNA-Ser(UGA) in the mature tRNA pool. We postulate that tRNA-Ser(CGA) elimination increases the translational demand for tRNA-Ser(UGA), a pressure relieved by increasing <i>serTGA</i> copy number. This work demonstrates that tRNA gene sets can evolve through duplication of existing tRNA genes, a phenomenon that may contribute to the presence of multiple, identical tRNA gene copies within genomes.
Medical subject headings
- DNA, Bacterial
- Gene Duplication
- Pseudomonas fluorescens
- RNA, Transfer, Ser