The Green Line

Does the recent creation of a "synthetic cell" mean than man has created life?

The short answer is, "Not exactly". But the longer answer is no consolation for anyone who thinks it can't happen, or can't happen soon. It raises difficult questions about what we mean by "create" and "life", and about some widely held ethical beliefs (such as the prohibition of murder) that presume there is a clear distinction between "living" and "non-living" entities.

First, a little background. Modern biology says that the control of all those properties that are required for an entity to be "living" is completely encoded in the genetic material (the "genome") of that entity. This view has been confirmed by thousands of experiments. It is beyond practical doubt.

For nearly thirty years, scientists have been modifying small portions of the genomes of naturally occurring species to create variants of existing, and arguably new, species, that produce pharmaceuticals and other highly useful chemicals on an industrial scale.

The so-called "synthetic cell" is an example of modest genomic modifications pushed to their logical limit. In a computer file created entirely by humans, Synthetic Genomics, Inc., a privately funded research company led by geneticist J. Craig Venter, specified the entire genetic code for a variant of a bacterium which did not exist. This file was effectively used as a program for a machine that, without using any living system, constructed pieces of genetic material corresponding to the computer specification. The pieces were then inserted into yeast cells, which in turn spliced the pieces to form a complete genome corresponding to the specification in the computer file. The synthesized genome was then removed from the yeast cells. All the genetic material was removed from a cell of an existing bacterial species, and the synthetic genome that had been removed from the yeast cells was then inserted into the bacterial cell from which the genetic material had been removed. The resulting organism immediately began consuming nutrients and replicating. By any generally accepted definition of "life", the new bacterium is a living being whose entire genetic code was conceived by humans and assembled from "piles of lifeless chemicals". Encrypted in the genome of the new organism are Venter's own initials, "JCV", along with a few valedictory and legal messages, forming a sort of genetic "watermark".

Whether this accomplishment amounts to "creating life" is a thorny issue, and the debate over the subject tells us more about how difficult it is to say what "create" and "life" mean, than it does about whether life has been created.

It might argued, for example, that the assembly of this new species falls short of "creation", because it required a (part of a) pre-existing living cell as a target, and because yeast cells were used to assemble the synthesized genetic pieces into a whole genome.

Although at least part of this objection to the claim that life has been created is certainly correct -- pre-existing living cells were used in the process -- once the original genetic material was removed from the target cell and the fully assembled synthetic genome was extracted from the yeast cells, the pieces were longer living in any generally accepted use of the word "living". Moreover, if, in order to claim that we had "created" something, we first had to create the materials out which that thing was made, we would have say that humans have never "created" anything because everything they have "created" has been assembled from something that already existed. That meaning of "create" is not the meaning we are using when we say we have "created" a road from asphalt or a building from concrete and steel.

There is something dissatisfying about this counterargument, however. What does it imply about the case of a diseased human heart that is replaced by an artificial one? Once the patient's original heart is removed, but before the artificial heart is implanted, the entity on the operating table (considered in isolation from life-support equipment) and the artificial heart are each a "pile of lifeless chemicals". Are we therefore "creating life" by implanting the artificial heart? Most people would be inclined to answer, "No". How is the case of "creating" a living bacterium from "piles of lifeless chemicals" different from an artificial heart transplant?

Not least, consider the following thought experiment. Imagine that over the next 10 years, the synthesized bacterium obliterates all evidence of prior life on this planet. Assume that a thousand years in the future, extraterrestrial biologists arrive on Earth, decode the genome, and conclude that the moniker "JCV" encrypted in that genome is proof of intelligent design. Would they be right, and if so, in what way?

For further information, see Daniel G. Gibson et al., "Creation of a bacterial cell controlled by a chemically synthesized genome", Science, http://www.sciencemag.org/cgi/rapidpdf/science.1190719v1.pdf.

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