A few years ago Venter's team produced the simplest form of life they could possibly manage by cutting bits out of the genome of a very simple bacteria. They kept on cutting bits out until they got to the point where if they lost any more genes then the cell just wasn't functional. The end result was a bacterium with a genome of around 500,000 base pairs. You could think of it as the lowest common denominator of life.
Now the team have stitched together a completely novel genome from scratch, but here's an interesting extract from an interview with Dr Venter:
How difficult was this?
At one time there was just one error in over a million base pairs, and we found that as a result you don't get life.
In explaining how complex a task it was Venter explains that anything worse than 99.9999% fidelity just doesn't work. That's astonishing. And when you combine it with the previous findings outlined above you realise that at root life is an exceptionally special and delicate phenomenon.