Synthetic life, is it possible?

Frankenstein's monster

In the previous two posts in this series we have seen that the generation of synthetic life in the laboratory is probably a process more difficult than some optimists imagine.

Let’s look at one of the latest experiments in synthetic biology: George Church and Nili Ostrov, Harvard biologists, are trying to build a strain of the bacterium Escherichia coli immune to all existing viruses. How? By changing its genetic code so that viruses do not understand it and cannot use the bacterial cellular machinery to reproduce. Since the genetic code is redundant, it is possible to replace one of the codons encoding the amino acid arginine (AGA) with another that also encodes the same amino acid (CGC), and all the genes of the bacterium would go on generating the same proteins. This would be done with several rare codons. But since viruses would continue to use the substituted codons, the bacterial cell machinery would no longer be able to understand the DNA of the virus. This part of the job is almost finished. When it is done, it would also be necessary to eliminate the transfer RNAs of the missing codons and ensure that they are not remanufactured, so that the cellular machinery can no longer use them.

Note that the work done so far is the manipulation of the data recorded in the DNA. It is equivalent to changing the information contained in the hard disk of a computer so that it stops using a certain instruction of the language of the machine, by replacing it with another equivalent instruction. We are still very far from synthetic biology in the strict sense. Will it be possible to synthesize life in the near future?

The first thing we must take into account is this: we don't know how life on Earth appeared. We will probably never know, because every trace of that event has disappeared. We will never discover a fossil of the first living being, and if we did, we wouldn’t know it was the first. Therefore, we cannot take advantage of what then happened, to be our guide while trying to reproduce it in the laboratory. Once life appeared, about 3500-4000 million years ago, that process was never repeated again. The first living beings made it impossible, by consuming all the organic matter spontaneously generated before life appeared. The spontaneous origin of life on Earth was a unique and unrepeatable event.

Optimistic positions regarding the possibility of building synthetic life in the laboratory are based on reductionism, a philosophical theory that argues that everything that exists can be explained in terms of the properties of the fundamental elements of matter (i.e. elementary particles). Note that this theory is philosophy, not science, for what it asserts has not been proven. In the best case it has been postulated, with the hope that everyone will accept it.

The problem is, not everyone accepts it. There are other philosophical theories besides and against reductionism. Let us look at a recent review:

Reductionism seems to have its great poverty in its wealth. Its appeal is indisputable... It gives an account of a simple, coherent, analyzable and intersubjective reality... Reductionism sets aside qualitative distinctions... and intends to keep the essential, the central, what appears as real after saying “this is nothing more than...” (Héctor Velázquez, “Monismo y reduccionismo epistemológico: una revisión desde la unidad/pluralidad aristotélica”. In Naturaleza y Libertad. Revista de estudios interdisciplinares 2:251-265, 2013).

Reductionism is very attractive, for we are used to face those things around us by applying the method of analysis, often followed by synthesis. As a child who receives a new toy, we tend, when facing a new object, to analyze it (i.e. break it down into its constituent parts), and then, if possible, synthesize it (i.e. rebuild it, putting its parts together, with the hope that the object will again work).

The bad news is, synthesis is not always possible. In the case of living beings, until now it has never been. We can dismember a living being in its constituent parts (analyze it), but if we reconstruct it again by joining those parts, the result is not a living being, but a dead being. And there is a big difference (an essential difference) between a living being and the same being dead.

The wish to act like this, to synthesize life, is very powerful. It is behind all the research in synthetic biology. It is also behind the myth of Frankenstein, expressed for the first time in Mary Shelley's novel, which has sometimes been pointed out as the first science fiction novel in history, although in fact there are older candidates.

Naturally, reductionist philosophy leads to the opinion that synthesizing life must be, not just possible, but relatively easy. But other philosophers disagree, and think that it may actually be impossible. Let us look at an example:

Against the analytical character of knowledge, that explains by dividing, the living being manifests itself essentially as a whole... The living being behaves as a system where the multiple causal interactions... reach such a level of complexity that it is not possible to disassemble them by a total reduction to the most elementary forms of a mechanistic explanation... In the living being the properties that define it are not in its "inside", in its constituent elements, as a naive [reductionist] would claim, but rather they are "relational properties" that emerge and are configured as a response to the environment. (Mariano Asla, Valeria Cantó-Soler, “¿Por qué el reduccionismo es un problema recurrente en biología?” In ¿Determinismo o indeterminismo? Grandes preguntas de las ciencias a la filosofía, ed. Claudia E. Vanney and Juan F. Franck, UFV 2018).

As you can see, in the current state of science, the answer to the questions posed by the titles of the three posts in this series could very well be much farther than we think, if ever.

The same post in Spanish
Thematic Thread on Synthetic and Artificial Life: Previous Next

Manuel Alfonseca