Genome Hunters Go After Martian DNA

 

Hot place: Some biologists want to send a DNA sequencing machine to Mars to search for life.
NASA – courtesy of nasaimages.org

 

 

J. Craig Venter may have just started a race to discover alien life on the Red Planet. 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 1) ___ 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 2) ___ 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 3) ___,” Rothberg told MIT 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 4) ___ 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, 5) ___ their DNA, and then transmitting the information to a remote computer, as would be required on an unmanned Mars mission.

 

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 6) ___. 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 7) ___ 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 8) ___ 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 9) ___,” 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 10) ___. 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 11) ___—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.

 

Life probably can’t survive the 12) ___ 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 13) ___ genome. Rothberg, also a media celebrity, has made news by sequencing the DNA of notables like James Watson, as well as of Neanderthals.

 

Venter 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 14) ___ 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.” Source: MIT Technology Review, October 2012

 

ANSWERS: 1) extraterrestrial; 2) DNA; 3) Mars; 4) life; 5) sequencing; 6) rover; 7) machine; 8) robot; 9) Earth; 10) planets; 11) water; 12) radiation; 13) human; 14) genomes

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