Chip Technology: Detecting DNA in space

Credit: NASA

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 (EAPS).

He is 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.

Christopher Carr

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."

The researchers reported their results in a paper published in the journal Astrobiology.

More information: online.liebertpub.com/doi/full/10.1089/ast.2012.0923

New Research Re-Calculates date of Moon's Magnetic Dynamo by 160 million years

Mosaic of the near side of the moon as taken by the Clementine star trackers. 

The images were taken on March 15, 1994. 

Credit: NASA

A multi-disciplinary team of international researchers has found evidence to suggest the moon's dynamo persisted until at least 3.6 billion years ago.

In their paper published in the Proceedings of the National Academy of Sciences, the team says this pushes back the date for the dynamo approximately 160 million years.

Currently, the moon has no global magnetic field, but analysis of rocks brought back by Apollo astronauts showed that it did at one time. To create such a field, the moon would necessarily have had some churning in its interior—a dynamo.

Evidence of a dynamo inside the moon has led scientists to propose different theories as to how it might have come about.

Some scientists suggest it might have been due to an impact that knocked the internals loose and set them moving for a period of time.

Others theorise it might have been more likely due to differences in heat distribution during radioactive decay, prompting liquid shifting.

Clément Suavet

The lead author, Clément Suavet is currently assigned to the MIT Department of Earth, Atmospheric and Planetary Sciences (EAPS).

To gain a better understanding of the moon's dynamo and how it might have occurred, researchers have been working to more clearly define when it came about, how strong it was and how long it lasted.

To that end, researchers with this latest effort went back to the moon rocks that started the whole debate.

Using newer technology to analyse the rocks, they found that they had, on average, fields of 13–70 microtesla—the higher readings are on a par with that of Earth's magnetic field.

More importantly, they found that the rocks showed that a dynamo existed as far back as 3.6 billion years ago.

 Suavet says, 'This new finding shoots down the idea of the dynamo forming due to a large impact.'

That's because other research has shown that no impacts large enough to cause a dynamo have occurred since approximately 3.72 billion years ago—well before the age of the samples found but that still doesn't reveal the actual cause.

Though they can't prove it, the group suggests the dynamo mostly likely occurred due to interaction with Earth's gravity—likening it to a tug-of-war between the solid mantel and the liquid core, resulting in a constant internal churning.

More information: Persistence and origin of the lunar core dynamo, PNAS, Published online before print May 6, 2013, doi: 10.1073/pnas.1300341110