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A case for the ancient origin of coronaviruses
Joel O Wertheim1, Daniel K W Chu, Joseph S M Peiris
1Department of Pathology, University of California, San Diego, California, USA. jwertheim@ucsd.edu
Journal of Virology
|April 19, 2013
Summary
Coronaviruses, found in bats and birds, appear much younger than their hosts. This study reveals coronaviruses are likely millions of years old, resolving evolutionary discrepancies.
Area of Science:
- Virology
- Evolutionary Biology
- Genomics
Background:
- Coronaviruses are zoonotic viruses with natural reservoirs in bats and birds.
- Previous molecular clock dating suggested a recent origin for coronaviruses (around 10,000 years ago).
- This conflicts with the ancient evolutionary history of their host species, which diversified millions of years ago.
Purpose of the Study:
- To resolve the discrepancy between the inferred young age of coronaviruses and the ancient age of their hosts.
- To re-evaluate coronavirus evolutionary history using advanced modeling techniques.
Main Methods:
- Applied realistic evolutionary models to coronavirus genomic data.
- Explicitly modeled variation in natural selection strength over time.
- Improved modeling of substitution saturation in viral genomes.
Main Results:
- The time to the most recent common ancestor (TMRCA) for all coronaviruses is likely far greater than previously estimated.
- Revised estimates suggest a TMRCA in the order of millions of years.
- The new models reconcile the evolutionary timescales of viruses and their hosts.
Conclusions:
- Coronaviruses possess a significantly older evolutionary history than previously thought.
- The revised evolutionary timescale aligns with the ancient diversification of their natural hosts.
- Advanced evolutionary modeling is crucial for accurate viral phylogenetics.
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