“CRection of life “, read the title of the Boston Herald in 1899.” Lower animals produced by chemical means. “The report described the work of the German-American marine biologist Jacques Loeb, who later wrote:” The idea now hovers before me that man himself can act as a creator, even in living nature. “
In fact, Loeb had simply made a ditch of non -fertilized sea bug by exposing it to a mixture of salts – it was not even about to create life in the laboratory. No scientist has ever done this. But this old dream today hovers on the discipline called synthetic biology, the very name of which seems to promise the creation of artificial life forms. Take one of the most spectacular results in this area: in 2010, scientists from J Craig Ventter Institutes of Maryland and California have announced that they had “the First self-reproduced self-reproductive synthetic cell».
However, it was not really the creation of life either, but rather a particularly brave (or frightening, depending on your point of view). The team had produced a bacteria of a species found in the wild, but with the DNA that scientists had assembled in the laboratory using chemical methods, modified to their own design (including a version coded by the DNA of the address of the Institute’s website).
Really doing a living thing from zero is another matter. Can we create the life of its basic and non-alive components again? Some scientists try it – last year, researchers in the United States and Europe reported a “roadmap”, as they said, “realize the vision of Building cells from molecular parts».
All forms of life on earth share the same chemical ingredients: DNA to code the hereditary messages of the genes, the protein to make enzymes that allow the chemical processes of life, lipids to make cell membranes, etc. And all living beings are made up of individual cells, which are intrinsically alive in themselves; The nurse Paul Laureat Nobel calls them the atoms of life. (I do not present myself in the argument to know if the viruses, which are exceptions to these rules, are really alive.) So, if we had to make versions of all these molecules using chemistry alone (and this can be done) and that we would assemble them in a way in a cell, could we create a life?
This is a questionable point, because we cannot even do that. Cells do not only assemble all their molecular components mixed in a test tube – they are far too complicated. Each cell that has ever existed was made by the division of an anterior cell: like Rudolf Virchow, the German physiologist who helped to promote cell theory in the 19th century, said: “Each cell comes from a cell”.
You have undoubtedly spotted the flaw on this image, it is that it had to start somewhere. Where does the first cell come from? In other words, how is life born? We don’t know, but there is no shortage of theories. In 1953, two scientists from the University of Chicago tested one of them – this life was born from a primordial soup of chemicals in the first oceans – by making amino acids (chemical ingredients of proteins) from mixtures of water, hydrogen, methane and ammonia. Echoing the titles of half a century earlier, Time magazine said that the experience was about to create a “Living molecule” (anything supposed to be).
However, life has started, it would certainly not have coherent at the same time: the increasingly complicated chemical entities had to develop from simpler, acquiring more and more attributes of truly alive. But the simple fact that life appeared at all on a planet which was once a little more than rock, water and simple molecular gases in the atmosphere shows us that making life from zero must be possible.
Certain parts of the cells assemble. In particular, the lipid molecules of our cell membranes will meet in hollow cell bags in water to protect their oily parts. Researchers in the Netherlands are trying to build a kind of miniature mounting chain to load such lipid bubbles with proteins. But there is no reason why DNA, proteins and others spontaneously stop in the positions they adopt in living cells. We have no idea how we could lead all these parts to organize in something alive.
However, would it not yet be rather without imagination to create life in our own image (or that of a bacteria)? Why not do it instead from totally different molecular components – to, so to speak, to write our own song of life and not just to make a cover version? It would indeed be incredible, but we have even less idea where to start. How to do things that do what DNA and proteins do, but are not these molecules?
What it really comes down to is the slightly embarrassing fact that scientists do not even agree on what “life” means in the first place. So, how would we know if we did it, if it does not look like life as we know it? Some researchers argue that “artificial life” based on computer – algorithms that can make copies of themselves, or that produce models that crawl through the screen, perhaps by mutating and evolving as you go – correspond to the criteria to be really alive. Last year, Google researchers described how The reproductive computer programs have spontaneously emerged Non-repairments when they had the capacity to join and separate. The Group leader Blaise Agüera Y Arcas argued that this “synthetic life is no different from natural life” because all life is only a kind of calculation.
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But that defines a very low bar – it is not far from claiming that the water generated by the CGI is really humid. For me, the “life created” must be able, at least metaphorically, to get out of the test tube. If this perspective soothes you, do not be afraid: scientists are not even about to do so. They barely understand the question.
Upon reading
Life of life by Carl Zimmer (Picador, £ 20)
Life as no one knows by Sara Imari Walker (Bridge Street, £ 25)
Synthetic biology by Jamie A Davies (Oxford University, £ 9.99)