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The ancient Virus World and evolution of cells
Eugene V Koonin1, Tatiana G Senkevich, Valerian V Dolja
1National Center for Biotechnology Information, National Library of Medicine, USA. koonin@ncbi.nlm.nih.gov
Biology Direct
|September 21, 2006
Summary
The ancient virus world concept suggests viruses evolved from a primordial gene pool before cells, with modern viruses descending from these early elements. This view links viral and cellular evolution, proposing viruses predate cells and co-evolved with them.
Area of Science:
- Virology
- Evolutionary Biology
- Genomics
Background:
- Recent genomic advances offer new insights into virus origins and evolution.
- Comparative genomics allows data-driven exploration of deep viral roots.
- Current views on virus evolution are being re-examined with new data.
Purpose of the Study:
- To propose a new, coherent scenario for virus origins and evolution.
- To link viral evolution models with parsimonious cellular evolution models.
- To explore the deepest roots of viruses using comparative-genomic data.
Main Methods:
- Comparative genomics to identify shared viral genes.
- Analysis of gene content in viruses versus cellular life forms.
- Review of current perspectives on virus evolution.
Main Results:
- Shared genes in diverse viruses, absent in cells, suggest an 'ancient virus world'.
- Viruses and selfish agents likely originated from a primordial pool of genetic elements predating cells.
- RNA viruses, followed by retroid and DNA viruses, evolved sequentially from this pool.
- The emergence of eukaryotic cells acted as a second major center for virus evolution.
Conclusions:
- The 'ancient virus world' concept, supported by shared viral genes, posits a continuous flow of virus-specific genes from precellular stages.
- This concept is supported by models of a complex, mixing precellular gene pool and eukaryotic cell origin via archaeo-bacterial fusion.
- The virus world concept and cell evolution models offer a cohesive view of life's history.
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