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A phylogenomic data-driven exploration of viral origins and evolution
Arshan Nasir1, Gustavo Caetano-Anollés1
1Evolutionary Bioinformatics Laboratory, Department of Crop Sciences and Illinois Informatics Institute, University of Illinois, Urbana, IL 61801, USA.
Science Advances
|November 25, 2015
Summary
Viruses originated from ancient cells, not modern ones, evidenced by shared ancient protein structures and widespread genetic transfer. This study reveals a universal tree of life and the "viral supergroup" origin.
Area of Science:
- Virology and Evolutionary Biology
- Genomics and Proteomics
Background:
- The evolutionary origin of viruses is a long-standing enigma due to their diverse molecular and functional characteristics.
- Existing hypotheses lack substantial data to explain the emergence of viruses.
Purpose of the Study:
- To investigate the evolutionary origins of viruses by analyzing protein structural and functional data from numerous cells and viruses.
- To establish the ancient origins of the 'viral supergroup' and identify patterns of genetic information transfer.
Main Methods:
- Comprehensive analysis of protein structural and functional data from thousands of cellular and viral proteomes.
- Phylogenomic analysis to reconstruct the universal tree of life and infer evolutionary relationships.
- Comparative analysis of viral and cellular proteomes to identify shared domains of ancient origin.
Main Results:
- Identification of widespread horizontal gene transfer events among viruses and cells.
- Discovery of ancient protein structural domains common to viruses with diverse replicons and hosts, also found in cellular proteomes.
- Evidence for the ancient origin of a 'viral supergroup' and its deep roots in cellular evolution.
Conclusions:
- Modern viruses likely evolved from multiple ancient, segmented RNA-genome-containing cells that coexisted with ancestors of modern cells.
- Viruses originated from ancient cellular forms, not from modern cellular counterparts.
- The findings provide a robust genomic and structural evidence-based model for viral and cellular co-evolution.
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