Horizontal gene transfer in aminoacyl-tRNA synthetases including leucine-specific subtypes.

Juliane C Dohm, Martin Vingron, Eike Staub

Max Planck Institute for Molecular Genetics, Department of Computational Molecular Biology, AG Protein Families and Cellular Evolution, Ihnestrasse 63-73, 14195, Berlin, Germany.

Journal of molecular evolution 2006 Oct

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Aminoacyl-tRNA synthetases catalyze a fundamental reaction for the flow of genetic information from RNA to protein. Their presence in all organisms known today highlights their important role in the early evolution of life. We investigated the evolutionary history of aminoacyl-tRNA synthetases on the basis of sequence data from more than 200 Archaea, Bacteria, and Eukaryota. Phylogenetic profiles are in agreement with previous observations that many genes for aminoacyl-tRNA synthetases were transferred horizontally between species from all domains of life. We extended these findings by a detailed analysis of the history of leucyl-tRNA synthetases. Thereby, we identified a previously undetected case of horizontal gene transfer from Bacteria to Archaea based on phylogenetic profiles, trees, and networks. This means that, finally, the last subfamily of aminoacyl-tRNA synthetases has lost its exceptional position as the sole subfamily that is devoid of horizontal gene transfer. Furthermore, the leucyl-tRNA synthetase phylogenetic tree suggests a dichotomy of the archaeal/eukaryotic-cytosolic and bacterial/eukaryotic-mitochondrial proteins. We argue that the traditional division of life into Prokaryota (non-chimeric) and Eukaryota (chimeric) is favorable compared to Woese's trichotomy into Archaea/Bacteria/Eukaryota.

Citation

Juliane C Dohm, Martin Vingron, Eike Staub. Horizontal gene transfer in aminoacyl-tRNA synthetases including leucine-specific subtypes. Journal of molecular evolution. 2006 Oct;63(4):437-47