DNA Transplant Transforms Bacteria
Scientists have completed another step on the road to creating synthetic life.
Researchers at the J. Craig Venter Institute in Rockville, Md., have taken the entire genome out of one bacterium, altered it, and reinserted it into a different bacterium.
Such genome transplants should soon allow scientists to create life from scratch.
In the form of bacteria, this synthetic life could clean up pollution or create new forms of biofuel.
The basic blueprint for life is written in long, stranded molecules known as DNA. Scientists can decode an existing genome by looking at the DNA one segment at a time. It's a bit like taking beads off a string.
John Glass, a researcher at the Venter Institute, wants to reverse the process. "We're adding new beads onto a string to make what we want," he says. What Glass's group would like to do is build a small genome of the type found in simple bacteria and set it to work. He says it could reveal a lot about what makes life alive.
"We're trying to understand how life works," Glass says. "What is in these organisms that makes this bag of chemicals be more than a bag of chemicals?"
The group already has shown how to make an artificial genome. They use a yeast cell as a kind of factory. The yeast's natural enzymes assemble the artificial genome from pieces of synthetic DNA. But an artificial genome in yeast doesn't do anything. To make it spring to life they need to get it into a bacterial cell.
That's not so easy. Yeast is a fungus, and bacterial immune systems attack foreign genetic material. Reporting this week in the journal Science, the group says it has solved that problem by shutting down the bacterial defenses.
They tested their technique using a nonsynthetic genome from one bacterial species common to goats. They put the genome in yeast, made a few small genetic modifications, and then implanted it in a different species of bacteria, whose immune system was suppressed. The surrogate accepted the new genetic material.
They still have to try it with an artificial genome. But the paper proves the last step needed to build synthetic life, says Drew Endy of Stanford University.
"All the steps of the process have been demonstrated," Endy says. "Anybody in the world could begin the good work of trying to figure out how living organisms work."
Endy hopes that this technology could eventually lead to cheap ways to produce pharmaceuticals or biofuels. It could be used for ill as well, he adds.
He thinks that the public and scientists should engage in a healthy public debate about how synthetic life can benefit society. "A lot has to do with who we are as human beings and how we choose to respect one another," Endy says.
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STEVE INSKEEP, host:
Scientists have moved one step closer to building life from scratch. The scientists in question work in the lab of Craig Venter, who's a pioneer of genetic research. In this week's issue of the journal Science, they describe their latest efforts. And NPR's Geoff Brumfiel reports.
GEOFF BRUMFIEL: I've always thought that to bring something inanimate to life, you need a castle, a lightning storm and a mad scientist.
(Soundbite of movie, "Frankenstein")
Mr. COLIN CLIVE (Actor): (as Dr. Henry Frankenstein) It's moving.
(Soundbite of thunder)
Mr. CLIVE: (as Dr. Henry Frankenstein) It's alive.
BRUMFIEL: But it turns out all you really need is an office building in suburban Maryland…
Unidentified Woman: Good afternoon, Venter Institute, may I help you?
BRUMFIEL: …some lab space, and these guys.
Dr. SANJAY VASHEE (J. Craig Venter Institute): My name is Sanjay Vashee.
Dr. JOHN GLASS (J. Craig Venter Institute): And I'm John Glass, professor in the synthetic biology department.
BRUMFIEL: Judging by their polo shirts and tidy haircuts, these two aren't mad scientists, but they are very, very close to creating life from scratch. It's not quite as crazy as it sounds. The basic blueprint for life is written in molecules known as DNA.
Dr. GLASS: It's a long molecule that's made up of carbon, phosphorous, oxygen and nitrogen, I think. And hydrogen. Of course. Duh.
BRUMFIEL: Yeah, duh. These five elements make up the genomes of every living thing, and scientists can decode an existing genome by looking at the DNA one segment at a time. It's a bit like taking beads off a string. To make new life, John Glass reverses the process.
Dr. GLASS: Now, instead, we're adding new beads onto a string to make what we want.
BRUMFIEL: His goals are modest compared to Dr. Frankenstein's. Glass's group wants to build the genome of a simple bacteria and get it working. He says that could reveal a lot about what makes life, well, alive.
Dr. GLASS: We're trying to understand how life works. What is in these organisms that makes this bag of chemicals be more than a bag of chemicals?
BRUMFIEL: The group already knows how to build a genome. They use a yeast cell as a kind of factory. The yeast strings together pieces of synthetic DNA. But to make the synthetic genome spring to life, Vashee says they need to put it into a bacterial cell.
Dr. VASHEE: We needed to put it together.
BRUMFIEL: That's not so easy. Yeast is a fungus, and the bacteria's immune system attacks foreign genetic material. The team has now solved that problem, though. They figured out how to shut down the bacterial defenses. Glass says that they tested it by transplanting a non-synthetic genome from yeast into a bacterial cell.
Dr. GLASS: Now, think of it as I took the software from one computer. Now, I took that software and I put it into another kind of computer, a different kind of cell.
BRUMFIEL: It worked. They still have to try with the synthetic genome. But even so, Drew Endy of Stanford University says that this provides the last step needed for synthetic life.
Professor DREW ENDY (Synthetic Biologist, Stanford University): All the steps in the process have been demonstrated, and that's the significant thing, all right. It means that anybody in the world could begin the good work of trying to figure out how living organisms work or use the same tools to make useful new things.
BRUMFIEL: Researchers want to eventually build bacteria that can clean up pollution or generate biofuels. Of course, the bacteria could be used for harm, as well. But Drew Endy says that's how it goes with all technology.
Prof. ENDY: We could all choose to go to the hardware store and purchase hammers, and instead of doing something useful with those hammers we could hit people directly and hurt folks.
BRUMFIEL: All the scientists involved hope that the creation of the first synthetic life will spark a healthy public debate. But that debate won't involve Frankenstein's monster. Even with all their skill, these scientists can only build a genome that's 6,000 times smaller than ours.
Geoff Brumfiel, NPR News.
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INSKEEP: This is NPR News. Transcript provided by NPR, Copyright National Public Radio.
