If you were setting out to design a human being from scratch, odds are you wouldn't take J. Craig Venter as your template. You wouldn't choose to put him at risk for Alzheimer's disease, for example, but Venter has a predisposition that places him in danger of it. You might choose his startling blue eyes, both for their color and the hard clarity of their gaze. You'd surely go for his first-rate brain, though you might pass on what his detractors consider the vainglorious temperament that comes bundled with it.
It's something of an irony then that such an imperfect organism as Venter has devoted much of his career to understanding the engineering of other organisms. He was the leader of one of two teams that in 2000 sequenced the human genomethe entire 25,000-gene cookbook that makes us people in the first place and not chimps or birds or banana trees and he has conducted the same work with many other organisms. But Venter, 61, may have just done something that is at once more thrilling and promising and unsettling than all that. According to a just-released paper in the journal Science, he has gone beyond merely sequencing a genome and has designed and built one. In other words, he may have created life.
Certainly, defining what we mean when we say life has become a moving target over the years. Are we alive? Yes. Is a virus alive? Maybe. Still, a half-century after the discovery of the double helix, nobody doubts that it is our DNA that determines what we are in the same way that lines of code determine software or the digital etchings on a CD determine the music you hear. Etch new signals, and you write a new song. That, in genetic terms, is what Venter has done. Working with only the four basic nucleotides that make up all DNA adenine, cytosine, guanine and thymine he has assembled an entirely new chromosome for an entirely new one-celled creature. Insert that genome into a cell like inserting a disc into a computer and a new species of living thing will be booted up. Venter hasn't done that yet, which is why even he won't say that he has technically invented life. He has, however, already shown that a genome transplanted from an existing cell to another will shut down the host's genetic programming and bring its own online. If that cellular body-snatching works with an ordinary chromosome, there's little reason to think it won't with a manufactured one. "The fact that this is even possible is mind-boggling to most people," Venter says.
That's not an overstatement. The genome in Venter's lab in Rockville, Md., could revolutionize genetics, introducing a new world order in which the alchemy of life is broken down into the ultimate engineering project. Man-made genomes could lead to new species that churn out drugs to treat disease, finely tuned vaccines that target just the right lethal bug, even cells that convert sunlight into a biofuel.
Creating such small, single-purpose organisms is nowhere near as complex as creating larger, multicelled creatures things with mobility, behavior, a purpose, a face. Those fanciful and frightful things are surely many years away and may prove too challenging and disturbing for society to allow. What Venter appears to have done, however, is crack the manufacturing code. Once you've done that, there may be little limit on what you can eventually build.