Synthetic Life

This was a big week for molecular biology geeks. Craig Venter and his team at the Venter Institute in Maryland announced that they had successfully created what they call “synthetic life.” Like Dr. Frankenstein, we have now created life from non-living material. Surely designer organisms that eat carbon dioxide and secrete oil are not far away, thereby solving both global warming and the energy crisis!

Well, maybe not.

When you get beyond the hype of the press release and examine what Venter’s team really did, it boils down to three things. 1) They completely decoded the DNA of an existing bacteria. This is known as sequencing the genome. 2) They artificially created a copy of the sequenced DNA, starting with the nucleotide bases that are the building blocks of the DNA molecule. As part of that process they modified some of the nonfunctional sections of the DNA to insert what are called “genetic watermarks.” 3) They took a different bacteria, removed the genetic material that was native to the germ, and implanted their prebuilt DNA. The newly implanted DNA then took over the machinery of the cell and began making copies of itself in the normal process of cell division.

These are all neat tricks, to be sure, and incredibly difficult to boot. But I think they fail two key tests for the claim of truly creating artificial life. First, true artificial life will have a genetic code designed from scratch. Venter borrowed the genetic code from an organism that had developed over a billion years of trial and error evolution.

Second, to be truly synthetic, they would have to combine their novel DNA with both a lab grown cellular membrane and built from scratch cellular metabolic machinery. If that assembly then began to grow and reproduce, then they could truly claim to have built an artificial life form.

We’re still a long way away from gleefully cackling “It’s alive! My creature lives!,” as we rub our hands together with glee. Consider: the bacterial DNA Ventner synthesized consisted of a little over one million base pairs, combined to make a single chromosome. Human DNA includes over three billion base pairs, spread out over 46 chromosomes. That’s three thousand times more genetic code.

Those caveats aside, it is still an astonishing technical achievement. Clearly with some fine tuning, they will soon be able to use their techniques to do the kind of design work mentioned above.