Now researchers are poised to cross a dramatic barrier: the creation of life forms driven by completely artificial DNA.
Scientists in Maryland have already built the world's first entirely handcrafted chromosome -- a large looping strand of DNA made from scratch in a laboratory, containing all the instructions a microbe needs to live and reproduce.
In the coming year, they hope to transplant it into a cell, where it is expected to "boot itself up," like software downloaded from the Internet, and cajole the waiting cell to do its bidding. And while the first synthetic chromosome is a plagiarized version of a natural one, others that code for life forms that have never existed before are already under construction.
Craig Venter, the iconoclast scientist who led part of the giant project to read the human genome, has not stopped there. Since the mid-1990s he's been on a quest to create nothing less than artificial life.
That's right, synthetic life--and today Venter and his team announce a major advance. They report, in the journal Science, that they have synthesized the genome -- the complete DNA -- of a bacterium called Mycoplasma genitalium.
"We consider this the second in significant steps of a three-step process in our attempts to make the first synthetic organism," Venter said this morning in a telephone briefing from Davos, Switzerland, where he's attending the World Economic Forum.
They picked the bacterium because it's relatively simple; while the DNA in human cells has three billion "base pairs" -- rungs, if you will, on that familiar spiral ladder you so often see -- M. genitalium has fewer than 600,000.
Venter talks of creating synthetic organisms that create energy to take the place of fossil fuels, or thrive by consuming toxic chemicals to allow easier cleanup. Perhaps, he says, some can be created that consume large amounts of carbon dioxide, helping to stave off climate change.
But, obviously, if he succeeds, Venter will raise all sorts of moral and ethical questions. He knows that, and, when he began, assembled a panel of bioethicists and others to consider the implications.
I spoke to Glenn McGee, who edits the American Journal of Bioethics, and was on the panel, and he urges caution. Will this project face the same political backlash as cloning? What if a bunch of people "with a bit of knowhow and a lot of anger" decided to create, say, synthetic anthrax?
Finally, he asks, isn't this playing God, with all that implies? Heavy stuff.