Pathogenic viruses represent a small fraction of viral diversity, and emerging diseases are frequently the result of cross-species transmissions. And the process of discovering these pathogenic bacteria through diseases involves two challenges- first is that it’s only the beginning of a long and painstaking process of identifying the infectious virus that caused it. The second is that it leaves out potentially deadly viruses that might emerge as a result of transmission from other species where they don’t show any clear signs of infection.
Therefore, we need to develop high-throughput techniques to investigate a broader range of viral biodiversity across a greater number of species. This is especially important in the context of new practices in agriculture that have arisen to tackle the challenges of global food security, including the rising number of marine and freshwater species that are used in aquaculture.
In this direction, a team of researchers from the Oxford University have discovered new viruses using DNA sequencing, making way for others working in the direction to detect miniscule amounts of a virus’s DNA that happens to be in the blood or tissue sample of a host.
Many scientists sequencing the DNA of animals or plants view this viral DNA as
a nuisance – rogue contaminants that need to be filtered from DNA sequencing results. But these scientists took a different view.What if the viral DNA was a missed opportunity?
So the scientists set out to test the idea that massive online DNA databases could be used as a resource to discover viruses – even if the data had not been explicitly collected for that purpose.
In the course of the study, they examined 50 genomes of fish and uncovered viral DNA in 15 fish species, including Atlantic salmon and rainbow trout.
The study demonstrated the utility of combining evolutionary approaches with bioinformatics to mine non-viral genome data for viruses, by adapting methods from paleovirology; thereby enabling simultaneous identification of sequences that likely represent endogenous viral elements, which we experimentally confirmed in commercial salmon samples.
The key to the success of this research is in its inter-disciplinary approach, combining techniques from two fields: evolutionary biology and genomics. Together, these are at the core of the new field of paleovirology – the study of ancient viruses that have integrated their DNA into that of their hosts, sometimes millions of years ago. Each technique used has been developed to analyse huge quantities of DNA sequence data.
Finding new viruses has historically not been an easy process. Cells do not grow on their own, so must be cultured in a laboratory before they can be analysed, which involves months of work. But the Oxford research represents a massive opportunity for the future.
The identification of novel viruses from genome data shows that the approach has applications in genomics, virology, and the development of best practices for aquaculture and farming.
