In contrast, Venter's self-named institute in Rockville, Md., is trying to create an artificial chromosome — the structure that carries DNA — that contains industrially useful genes such as ones that could help produce alternative fuels.
That work is far from complete, but to make it work, they'd have to put the artificial chromosome into a living cell and it would have to jump-start that host. Thursday's experiment was designed just to prove an entire-genome switch is possible, with regular bacteria DNA.
The Venter team picked two Mycoplasma species, simple germs that contain a single chromosome and lack the cell walls that form barriers in other bacteria. First, they added genes to turn the donor bacteria an easy-to-spot bright blue, and to make it resist an antibiotic used to kill off any host germ that retained its own genes.
Then they stripped off the donor chromosome's proteins, to see if naked DNA alone could "reboot" a foreign cell. Blue germs appeared within days of dropping the genome into lab dishes containing the second bacteria. Not many: only about one in every 150,000 cells took up the donor genome and grew, but they bore no evidence of the original DNA.
"That's extremely inefficient," acknowledged lead scientist John Glass, a Venter Institute microbiologist. "We think we can steadily improve this."
"Synthetic genomics still remains to be proven, but now we are much closer to knowing it's actually theoretically possible," added Venter.
It's not clear that the method would work on larger, more complicated bacteria, other specialists cautioned. Nor does the work automatically mean an artificial chromosome alone could activate a living cell.
"It's going to be much more complicated to do with synthetic organisms," said Dr. Jonathan Eisen, an evolutionary biologist at the University of California, Davis. Still, "it's a great first step."
