The LUCA and its complex virome

Mart Krupovic (1) , Valerian Dolja (2) , Eugene Koonin (3)

1 Virologie des archées - Archaeal Virology
2 Department of Botany and Plant Pathology
3 NLM - National Library of Medicine

The last universal cellular ancestor (LUCA) is the most recent population of organisms from which all cellular life on Earth descends. Reconstruction of the genome and phenotype of the LUCA is a major challenge in evolutionary biology. Given that all life forms are associated with viruses and/or other mobile genetic elements, there is no doubt that the LUCA was a host to viruses. Here, by projecting back in time using the extant distribution of viruses across the two primary domains of life, bacteria and archaea, and tracing the evolutionary histories of some key virus genes, we attempt a reconstruction of the LUCA virome. Even a conservative version of this reconstruction suggests a remarkably complex virome that already included the main groups of extant viruses of bacteria and archaea. We further present evidence of extensive virus evolution antedating the LUCA. The presence of a highly complex virome implies substantial genomic and pan-genomic complexity of the LUCA itself.

Mots clés: Evolution; Virology

Domaines: Virologie; Sciences du Vivant [q-bio]; Microbiologie et Parasitologie

Mart Krupovic, Valerian Dolja, Eugene Koonin. The LUCA and its complex virome. Nature Reviews Microbiology, 2020, 18 (11), pp.661-670. ⟨10.1038/s41579-020-0408-x⟩. ⟨pasteur-02909671⟩