May 21 2010

Artificial Life

Well – not quite. But Dr. Craig Venter’s lab has made an significant advance in crafting synthetic bacteria. This is an advance we have been anticipating, as Venter has not been shy about promoting his research program.

What he has accomplished now is the following: He has sequenced the genome of a specific species of bacteria, then manufactured a copy of the DNA entirely with a sequencer. The synthetic copy was then inserted into a bacterium of a different species whose own genome had been removed. The bacterium then transformed into the species of the synthetic genome it had received, and was able to reproduce normally as the new species.

So, the end result was just a normal bacterium of an existing species. But this is a significant proof of concept. First, it showed that they can manufacture a bacterial genome that will be fully functional. Second they demonstrated that this genome can function in a bacterium, even of other species, and will completely control the machinery and therefore function of that bacterium. And finally, the bacteria can reproduce normally.

Essentially, the technology is now fully in place to begin experimenting with artificial bacterial genomes. This ultimately is just another method of genetic engineering. We are already able to significantly genetically engineer bacteria and have been doing so for years for a variety of applications, such as drug production. But this technique affords a higher level of direct control. You can design your bacteria in a computer, and then mass produce it.

But beyond genetic engineering, this technology gives the potential for genetic construction from the ground up. Venter and his colleagues can use this technique to systematically experiment on the bacterial genome, changing any part of it they wish, until they reverse engineer how to build a bacterial genome. They would not be starting from scratch – we already know a great deal about bacterial genetics and proteomics, but this will take that knowledge to a higher level. Ultimately this could lead to the design of bacteria from scratch based upon a thorough understanding of basic design principles. And of course, bacteria are only the beginning – eukaryotes could be next.

As is typical, proponents of this new technology are emphasizing its potential benefits while critics are warning of its potential dangers and abuses. Any new powerful technology has the potential for both, and this is no exception. Venter points out that engineered bacteria could be used to clean up the environment and as a source of synthetic fuel. There are also many potential medical applications – designing bacteria to colonize our oral cavity and gastrointestinal tracts to prevent infections, aid in digestion, eliminate tooth decay, and other possibilities.

This could also be a source of biowarfare. And, even without nefarious intentions, releasing new bacteria into the environment can have unintended consequences – although I think doomsday scenarios are exceedingly unlikely. But it is always reasonable to consider the potential downside to a new technology and use regulation and security to minimize risk.

In the short term this is really just an incremental advance – a new way to do something we can already do, genetically engineer bacteria. But this technique puts us on a path to far greater control. It will probably still be years before we see the full potential of this technology, and it will definitely be something to keep a close eye on.

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