The ‘synthetic life’ experiment is a case of magnificent genetic engineering
PUSHPA M BHARGAVA
Beginning with Leonardo da Vinci in the 15th century, one of the most important european projects after the Renaissance was the recognition of the laws of chemical combination, which told us how compounds were made from elements — for example, water from hydrogen and oxygen. This paved the way for synthetic chemistry — one of the greatest accomplishments of mankind. Yet, for centuries afterwards, it was believed that chemicals found in living organisms cannot be synthesised in the lab as they contained a “vital force” akin to the elusive “spirit” or “soul”, which we now know does not exist. This belief was shattered first by Friedrich wohler who, in 1828, synthesised urea, found in living organisms, in the lab. today, we can synthesise every chemical constituent found in living organisms from its elements. But can we synthesise a cell which is the unit of life and consists entirely of chemicals? The answer is, no.
Craig Venter’s claim, made in a recent issue of Science, of making synthetic life, is therefore, untenable and unjustified. This is not to underrate the value of his work. we all know that DNA is the genetic material. in living cells, DNA is organised in structures called chromosomes. a chromosome consists of a large number of genes that are the unit of heredity. a change in the sequence of the four building blocks (A, G, C and t) of a gene (and therefore of dna), can give rise to a disease such as thalassemia. we have, if we are normal, 46 chromosomes which together contain some 30,000 known genes.
In conventional genetic engineering, we take one, two or a few — genes from one organism that code from a desirable function, and put them in another organism that doesn’t have the genes, in such a way that we can (often commercially) exploit the process. an example would be the large-scale production of human insulin by a genetically modified yeast.
What Venter has done is massive genetic engineering. He synthesised a whole designer chromosome and put it in a bug in a way that the bug recognised the chromosome as its own and replicated, but now following the instructions contained in the foreign chromosome, and thus essentially altering the nature and character of the recipient organism. in other words, he radically transformed a living cell in a way and to an extent that had not been done before. he didn’t synthesise life.
To synthesise life, you have to do something like what wohler did, but on an immensely larger scale. Let us see what one needs to do to justify a claim of having synthesised life.
Craig Venter’s claim of making synthetic life is untenable, but his work cannot be underrated
We have to first define the minimum requirement for a cell, that is, the minimum set of chemicals that a cell must contain. we must then be able to take these chemicals (such as proteins, dna, lipids, carbohydrates, and metabolites) individually, and put these together in one or a series of steps, in such a way that a cell is formed that would satisfy the criteria of life, like the original cell from which the chemicals were derived. These criteria are: (a) ability to replicate; (b) ability to metabolise and, in the process, convert one form of energy into another; and (c) amenability to change (in technical terms, undergo a mutation). Venter’s work — in spite of it being very exciting, very beautiful, very important, and very difficult — does not meet the above criteria of synthetic life.
This work will not get Venter a nobel Prize, which anyone who synthesises a living cell — the unit of life — is bound to get. however, Venter’s work has the potential of, on the one hand, defining the minimum requirements (in terms of chemical constituents) for a viable cell defined as above, while, on the other hand, it has built-in hazards of producing through genetic engineering, unimaginably lethal biological weapons. Venter’s achievement has all the potential risks and benefits associated with conventional genetic engineering.