Colonizing and terraforming another planet is no easy task; if we let this adventure slip away someday, we may well need viruses to make it happen.
The idea of colonizing other planets is on the rise at the moment. She even finds a particularly active ambassador in the person of Elon Musk. For years the whimsical founder of SpaceX has been telling anyone who will listen to his dream of moving to the Red Planet; in the long term, its objective would even be to terraform it, that is to say to modify its environment so that it is compatible with life from Earth. This implies in particular to radically modify conditions on site; but if we want these modifications to be able to give life to a “second Earth”, which would be a perennial clone of our planet, this also implies importing its biodiversity.
The complexity of such a mission is in many ways beyond anything humanity has yet undertaken. It is therefore not surprising that many observers find the idea absurd; to play the architects of life on a planetary scale, it will be necessary to take into account many factors that still completely escape us today. And according to renowned astrobiologist and cosmologist Professor Paul Davies, one of the missing pieces of the puzzle is certainly on the side of viruses.
Viruses, vectors of genetic diversity
This deduction starts from a simple observation: life as we know it on Earth is a phenomenon of crazy complexity, which goes far beyond the simple physical and chemical context. It is the fruit of a very fine dynamic, supported by the links which unite the various actors of the living; Davies even speaks of a “web of life”, Of which viruses are an integral part despite their decidedly negative image in popular culture – especially during a pandemic.
Physiologically, viruses are little pirates; they exploit the cellular machinery of their host to reproduce. But the machinery in question is not infallible, far from it. It can make mistakes, which in turn can lead to the integration of genetic material from the other species. This results in a phenomenon called horizontal gene transfer, as opposed to the vertical transmission of genes to offspring during reproduction.
However, we now know that this horizontal transmission is a very important factor of genetic dispersion; viruses therefore actively participate in the evolutionary history of different species. Many studies suggest, for example, that a significant part of our genome comes directly from this source. On a larger scale, they therefore represent an essential component of the ecosystems that we know.
Pigs, tomatoes … and viruses
To truly terraform Mars, lay the foundations of life as we know it and prosper there, this biological component would therefore be crucial; our technology alone would not be enough, Davies said. “The most complicated part of this problem is the microbiology that we should take away. It would not be enough to bring some tomatoes and a few pigs, and think that everything would be beautiful and viable in the long term.”, Explains the researcher; we will also have to take viruses in our suitcases.
Obviously, he is careful not to offer instructions for the use of viruses in the context of the colonization of other planets, because the question is not there. The issue of the place of viruses in this major project is obviously interesting to study; but what Davies’ interview highlights is our very restricted view of this set of intertwined phenomena that animate our ecosystems. It will be essential to better understand them if we wish to recreate an ecosystem from scratch, far from our earthly cradle.