Nearly 1,500 new virus species discovered by international research team
Almost 1,500 new virus species was discovered by a team of international researchers led from Australia and China. The study significantly expands the existing catalogue of known viruses and also indicates that these viruses have existed for billions of years.
The international team of scientists surveyed a group of animals called invertebrates – a group of spineless creatures which includes insects, spiders, worms and snails – for new viral species. Invertebrates represent the vast majority of animal species in the world today.
They used next-generation sequencing techniques to get new insight into the magnitude of the invisible world of viruses, known as virosphere. These techniques reveal the genetic “calling cards” of the viruses and they are present in the things that they infect.
For humans and other animals, DNA (deoxyribonucleic acid)is the “stuff of life”. It makes up the blueprint of our genomes. But many viruses use a different chemical to construct their genomes – a substance known as RNA (ribonucleic acid).
Much like DNA, RNA consists of strings of individual building blocks, or bases that are each designated by a different letter: A, C, G and U.
Next-generation sequencing allows researchers to quickly determine the sequence of these letters. And if you work out the order of the letters on any chain of RNA, you can determine if it belongs to a virus and whether or not the virus is new.
The technique offers a huge potential for virus discovery.
Around 220 species of land- and water-dwelling invertebrates living in China were collected by the research team. The scientists then extracted the RNA from the samples and, using next-generation sequencing, deciphered the sequence of a staggering 6 trillion letters present in the invertebrate RNA “libraries”.
When the researchers analyzed this mass of data they realized that they had discovered almost 1,500 new virus species – a whopping number by any measure. Many of these were so distinct that they did not easily fit into our existing virus family tree.
Even though some invertebrates carry viruses that can infect humans – like Zika and dengue – the study authors do not think that these newly discovered viruses pose a significant risk.The research also showed that throughout time viruses have been trading genetic material to create new species.
These studies not only expand the view into the diversity of viruses, they also provide a more complete picture of virus history.
Professor Edward Holmes from the University of Sydney, who was involved in the study explained: “We have discovered that most groups of viruses that infect vertebrates – including humans, such as those that cause well-known diseases like influenza – are in fact derived from those present in invertebrates.”
He also believes that his group’s data shows that viruses have been infecting invertebrates for possibly billions of years, raising the prospect that invertebrates are the true hosts for many types of virus.
The researchers hope that next-generation sequencing can pave the way for virus discovery in a variety of other species.
