January 31, 2008

"New life"

ResearchBlogging.orgThere's been a lot of interest in the media concerning the results published by the J. Craig Venter institute last week in Science - the synthesis of a completely artificial genome, or rather, the synthesis of a down-sized replica of the genome of the bacterium Mycoplasma genitalium.

The words "playing god", "man-made life" and "building new life from scratch" have been thrown around, unfortunately; not only because it makes synthetic biology more controversial than it needs to be, but because in essence they're wrong. Carl Zimmer has written two excellent pieces explaining the actual achievement and clearing out the misconceptions; but in short, terms like "playing god" or "creating new life from scratch" are inaccurate because technically you'd have to insert the artificial genome into a host cell and produce a viable organism, one that could replicate itself, before you'd have created life. Theoretically this isn't impossible or even particularly incredible, but it poses a whole lot of technical demands. And would this life actually really be "new" or even entirely synthetic?

Aside from this, actual living organisms, "old life", are still required to carry out the essential parts of the process for us. Both E. coli bacteria and baker's yeast, Saccharomyces cerevisiae, common biological model organisms, were required in this case. They're like little biochemical factories doing the job for us, putting the artificially synthesized blocks of DNA together to form the genome, basically a bigger ring-shaped DNA molecule. It's still largely unknown how they do it.

I'd also put the extra demand that this new organism would have to "do" something new in order to be called a true new organism. Its genome would have to be engineered in a way that allowed it to do something that no other living organism before it has done. Something like producing new "engineered" gene products or catalyzing new and exciting biochemical reactions. That would be seriously awesome. The J. Craig Venter institute speculates:

Scientists foresee many potential positive applications including new pharmaceuticals, biologically produced (“green”) fuels, and the possibility of rapidly generating vaccines against emerging microbial diseases.

So all in all it seems we are quite a bit away from "playing god". Not even when an artificial genome has been introduced into a host cell, creating a viable "new" organism, will we be even close to knowing how evolution has built genomes and how all of its parts interact to produce life. We're not making life, we're cheating by using bits and pieces of "old" life and putting it together in "new" ways. Carl Zimmer writes:

When and if Venter’s team does create a viable synthetic life form, our ignorance will still remain profound. <...> Scientists have gotten very good at manipulating genes--at copying them or using them to make biotechnology products like insulin--but they still know relatively little about how genes work together in living things.

Who knows if we will ever be able to create something entirely new. But the journey there seems like a pretty decent goal all in itself.

Gibson, D.G., Benders, G.A., Andrews-Pfannkoch, C., Denisova, E.A., Baden-Tillson, H., Zaveri, J., Stockwell, T.B., Brownley, A., Thomas, D.W., Algire, M.A., Merryman, C., Young, L., Noskov, V.N., Glass, J.I., Venter, J.C., Hutchison, C.A., Smith, H.O. (2008). Complete Chemical Synthesis, Assembly, and Cloning of a Mycoplasma genitalium Genome. Science DOI: 10.1126/science.1151721

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