Producing living beings with new characteristics by an artificial synthesis of a minimal genome to then transplant it into a living cell
On 24th March this year, an article by Craig Venter and his team was published in Science, in which they described how they obtained an organism with the smallest genome of any known form of cell life. Furthermore, the genome was synthesised artificially in the laboratory.
This study represents a new milestone in Synthetic Biology, which combines engineering and biology to obtain living beings with new characteristics. One branch of Synthetic Biology, Synthetic Genomics, consists in the artificial synthesis of a minimal genome (a genome that contains the essential genes that enable an organism to live) to then transplant it into a living cell. One potential application of this minimal genome is to make a “genome chassis” to which other genes can be joined to achieve specific functions. Moreover, the essential genes are potential targets for new antibiotics, as they are necessary for bacteria to survive.
In 2010, investigators from the J. Craig Venter Institute managed to synthesise a completely artificial simple bacterial genome (although not the most simple), successfully inserting it into a bacterium from which the genome had been removed, so that the synthetic genome took control of bacterial development. Now, six years later, these investigators have managed to minimize the synthetic genome from 901 genes to 473, i.e. they have eliminated 428 non-essential genes. This is the closest scientists have been to obtaining a cell in which the function of each gene is known, although the function of 149 of the 473 genes — which accounts for around one third of the total genome — is not yet understood.
Implications in the definition of the concept of life
Whilst these discoveries could have very valuable applications, their usefulness must be limited to these, since some scientists have suggested that these discoveries could have implications in the definition of the concept of life. Thus, the meaning of life, the properties shared by all living beings, could be deduced from the minimal genome. If the traits of an organism are determined by its genome, then the characteristic of being alive would be determined by a specific set of genes, and the rest of the genome would provide the organism with additional characteristics. Nevertheless, while a minimum number of genes may be sufficient for a specific organism to live, it will not be sufficient in order for a different organism to survive. In fact, the set of essential genes is different for each type of organism, and its survival can be guaranteed only under the most favourable conditions. Furthermore, this is a reductionist view, unable to see the concept of life as something more than merely physical. It seems more appropriate to leave this type of reasoning to philosophy and metaphysics, which correspond to the treatment of facts that cannot be scientifically examined.