Extraction of Deep Phylogenetic Signal and Improved Resolution of Evolutionary Events within the recA/RAD51 Phylogeny

TL;DR

This study enhances understanding of the deep evolutionary history of the recA/RAD51 gene family by employing advanced phylogenetic methods and extensive taxon sampling, revealing new insights into its diversification across domains.

Contribution

The paper introduces novel phylogenetic algorithms and analytical tools that improve resolution of recA/RAD51 evolutionary relationships and uncover previously unrecognized sub-families.

Findings

Refined phylogenetic tree of recA/RAD51 family.

Identification of new RAD51 sub-families.

Insights into the diversification of homologs in eukaryotes.

Abstract

The recA/RAD51 gene family encodes a diverse set of recombinase proteins that effect homologous recombination, DNA-repair, and genome stability. The recA gene family is expressed in almost all species of Eubacteria, Archaea, and Eukaryotes, and even in some viruses. To date, efforts to resolve the deep evolutionary origins of this ancient protein family have been hindered, in part, by the high sequence divergence between families (i.e. ~30% identity between paralogous groups). Through (i) large taxon sampling, (ii) the use of a phylogenetic algorithm designed for measuring highly divergent paralogs, and (iii) novel Evolutionary Spatial Dynamics simulation and analytical tools, we obtained a robust, parsimonious and more refined phylogenetic history of the recA/RAD51 superfamily. Taken together, our model for the evolution of recA/RAD51 family provides a better understanding of ancient origin of recA proteins and multiple events leading to the diversification of recA homologs in eukaryotes, including the discovery of additional RAD51 sub-families.