Detecting DNA in space
Researchers, in a step toward analyzing Mars for signs of life, find that gene-sequencing chip can survive space radiation.
If there is life on Mars, it’s not too farfetched to believe that such Martian species may share genetic roots with life on Earth.
More than 3.5 billion years ago, a blitz of meteors ricocheted around the solar system, passing material between the two fledgling planets. This galactic game of pingpong may have left bits of Earth on Mars, and vice versa, creating a shared genetic ancestry between the two planets.
Such a theory holds great appeal for Christopher Carr, a research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences. Working with Gary Ruvkun at Massachusetts General Hospital (MGH) and Maria Zuber, the E.A. Griswold Professor of Geophysics and MIT’s vice president for research, Carr is building a DNA sequencer that he hopes will one day be sent to Mars, where it can analyze soil and ice samples for traces of DNA and other genetic material.
Now in a step toward that goal, Carr and colleagues at MIT, Harvard University and MGH have exposed the heart of their tool — a DNA-sequencing microchip — to radiation doses similar to those that might be expected during a robotic expedition to Mars. After exposure to such radiation — including protons and heavy ions of oxygen and iron — the microchip analyzed a test strain of E. coli, successfully identifying its genetic sequence.
Carr says the group’s results show the microchip can survive up to two years in space — long enough to reach Mars and gather data there for a year and a half.
“Over time on Mars, a chip’s performance could degrade, reducing our ability to get sequence data. The chip might have a higher error rate, or could fail to function at all,” Carr says. “We did not see any of these issues [in our tests]. … Once this chip has been through two years of a Mars mission, it still will be able to sequence.”
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