Thursday, October 18, 2012
Two high-profile entrepreneurs say they want to put a DNA sequencing machine on the surface of Mars in a bid to prove the existence of extraterrestrial life.
In what could become a race for the first extraterrestrial genome, researcher J. Craig Venter said Tuesday that his Maryland academic institute and his company, Synthetic Genomics, would develop a machine capable of sequencing and beaming back DNA data from the planet.
Separately, Jonathan Rothberg, founder of Ion Torrent, a DNA sequencing company, is collaborating on an effort to equip his company's "Personal Genome Machine" for a similar task.
"We want to make sure an Ion Torrent goes to Mars," Rothberg told Technology Review.
Although neither team yet has a berth on a Mars rocket, their plans reflect the belief that the simplest way to prove there is life on Mars is to send a DNA sequencing machine.
"There will be DNA life forms there," Venter predicted Tuesday in New York, where he was speaking at the Wired Health Conference.
Venter said researchers working with him have already begun tests at a Mars-like site in the Mojave Desert. Their goal, he said, is to demonstrate a machine capable of autonomously isolating microbes from soil, sequencing their DNA, and then transmitting the information to a remote computer, as would be required on an unmanned Mars mission. (Hear his comments in this video, starting at 00:11:01.) Heather Kowalski, a spokeswoman for Venter, confirmed the existence of the project but said the prototype system was "not yet 100 percent robotic."
Meanwhile, Rothberg's Personal Genome Machine is being adapted for Martian conditions as part of a NASA-funded project at Harvard and MIT called SET-G, or "the search for extraterrestrial genomes."
Christopher Carr, an MIT research scientist involved in the effort, says his lab is working to shrink Ion Torrent's machine from 30 kilograms down to just three kilograms so that it can fit on a NASA rover. Other tests, already conducted, have determined how well the device can withstand the heavy radiation it would encounter on the way to Mars.
NASA, whose Curiosity rover landed on Mars in August, won't send another rover mission to the planet before at least 2018 (see "The Mars Rover Curiosity Marks a Technological Triumph"), and there's no guarantee a DNA sequencing device would go aboard. "The hard thing about getting to Mars is hitting the NASA specifications," says George Church, a Harvard University researcher and a senior member of the SET-G team. "[Venter] isn't ahead of anyone else."
Many scientists are lobbying NASA for what's called a "sample return" mission–one that would make a round trip, bringing back soil and rocks for analysis. However, taking a DNA sequencing machine to Mars could be a better way to search for life.
"The reason to take a device all the way to Mars and not bring back the sample is because of contamination. No one would believe you," says Tessi Kanavarioti, a chemist who carried out early theoretical work on Martian biology and was involved in studying rocks brought back from the moon in the 1970s. Sequencing machines are so sensitive that if a single Earth germ landed on the sample returned from Mars, it might ruin the experiment.
Martian chronicler: A microfluidic device developed at MIT is designed to automatically run DNA experiments on other planets.
Credit: Christopher Carr | MIT
Looking for DNA on Mars won't be easy. A robot would have to scoop up soil and prepare a sample automatically. The sequencing machine would need to work in cold temperatures and in a very thin atmosphere made mostly of carbon dioxide. Martian genes might also be different from those in the bodies of terrestrial animals, perhaps being made up of different chemical building blocks.
"This will work only if the DNA on Mars is exactly the same in its fundamental structure as on Earth," says Steven Benner, president of the Foundation for Applied Molecular Evolution in Gainesville, Florida. He says he's skeptical that will be the case: "It is very unlikely that Terran DNA is the only structure able to support Darwinian evolution."
Discovering and sequencing extraterrestrial life would be an immense scientific prize. Sequencing could reveal whether life evolved in similar ways on both Earth and Mars or, perhaps, moved between the planets. During a series of massive space collisions around four billion years ago, the two bodies exchanged about a billion tons of rocks and debris.
So far, NASA researchers have searched Mars for traces of water—a prerequisite for life as we know it—as well as indirect signs that life might have existed there many eons ago. Since DNA molecules don't survive more than a million years, even on Earth, anyone sending a DNA sequencer to Mars has to believe that living microorganisms will be found there now.
"The current NASA approach is to look for past life. Many people are reticent to talk about extant life," says Carr. "We are sticking our necks out a little bit, but we want to take that leap."
Life probably can't survive the radiation on the Martian surface, but it could exist under a meter or more of soil, where it would be protected. On Earth, for instance, living microorganisms are found several kilometers beneath the ground.
Carr calls sending a DNA sequencer to Mars a "high-risk, high-payoff" experiment. It might very well find nothing, but if DNA were discovered, that would provide nearly irrefutable proof of extraterrestrial life.
The slim odds apparently appeal to both Venter and Rothberg, two of biotechnology's biggest showmen. A decade ago, Venter gave academic researchers heartburn with his privately financed effort to sequence the human genome. Rothberg, also a media celebrity, has made news by sequencing the DNA of notables like James Watson, as well as of Neanderthals.
"We want our name out there," Rothberg says. "[Mars] is a corporate opportunity, but we think our technology is faster and better, too."
In an e-mail, Venter's spokeswoman downplayed the idea of any competition to discover extraterrestrial DNA first. "[I] wouldn't say there is any race," she said. "Yes [the] idea is that we would do it, but that certainly doesn't preclude anyone else from doing it."
Venter also said it might be feasible in the future to reconstruct Martian organisms in a super-secure laboratory on Earth, using just their DNA sequence. The idea would be to use the DNA data to rebuild their genomes and then inject those into an artificial cell of some kind. It's an idea he calls the "biological teleporter."
"People are worried about the Andromeda strain," says Venter. "We can rebuild the Martians in a P-4 spacesuit lab instead of having them land in the ocean."