viruses played a key role in the origin of life

In a study conducted in the Yellowstone Hot Springs, researchers sequenced the DNA of the algae that live there, and found 25 types of viruses in their genes. These genes may have helped algae adapt 1.5 billion years ago.

We discover that 1.5 million years ago, viruses helped life develop on Earth. Mathilde Fontez, editor-in-chief of the scientific magazine Epsiloon tells us for once about the positive effects of viruses, because there are…

franceinfo: An American study shows that viruses played a key role in the origin of life?

Mathilde Fontez: Yes, this team conducted a field study in the Yellowstone Hot Springs, USA. It is a hotbed of research into the origin of life: these very hot bubbling streams and lakes are thought to be quite close to the conditions in which life developed. This is where it all started: the first cells, the first organisms billions of years ago…

The researchers studied the algae found there today, red algae, from which they took samples and sequenced the DNA. And in their genes, they found viruses. Lots of viruses: they reconstructed 25 types precisely. These viruses reproduce by infecting red algae, and they insert themselves into their genes.

And these are old viruses?

Yes. This is the discovery of these researchers: from genetic sequencing, they reconstructed the family tree of these viruses, and found a very ancient link with the algae which shelter them today. These viruses were there from the beginning of the history of life, when these algae formed. Researchers see this in particular in the adaptation of viruses to environmental conditions.

Yellowstone’s streams are extreme: they are over 40 degrees, very acidic, very concentrated in toxins like arsenic. Viruses have been adapted to these Dantean conditions for a very long time: researchers conclude that their association with algae dates back 1.5 billion years.

Is it the alliance with these viruses that would have allowed the algae to develop?

This is what these observations suggest: viruses are particularly genetically plastic: they easily take over genes from bacteria, for example, which they transmit to the organisms they infect. They would have given the algae the right genes to resist, to develop. They would have helped them adapt. In short, before giving us colds, or covid, viruses worked on the development of life.