DNA Can Survive Reentry from Space

http://www.scientificamerican.com/article/dna-can-survive-reentry-from-space/?WT.mc_id=SA_HLTH_20141202

November 26, 2014 |By Dina Fine Maron

If a cascade of meteors struck Earth billions of years ago, could they have deposited genetic blueprints and forged an indelible link between Earth and another planet?

Perhaps. Although that puzzling question remains unanswered, scientists have uncovered a new clue that suggests it is possible for DNA to withstand the extreme heat and pressure it would encounter when entering our atmosphere from space.

In a new study published today in PLOS ONE, a team of Swiss and German scientists report that they dotted the exterior grooves of a rocket with fragments of DNA to test the genetic material’s stability in space. Surprisingly, they discovered that some of those building blocks of life remained intact during the hostile conditions of the flight and could pass on genetic information even after exiting and reentering the atmosphere during a roughly 13-minute round trip into space.

The findings suggest that if DNA traveled through space on meteorites, it could have conceivably survived, says lead author Oliver Ullrich of the University of Zurich. Moreover, he says, “DNA attached to a spacecraft has the potential to contaminate other celestial bodies, making it difficult to determine whether a life form existed on another planet or was introduced there by spacecraft.”

The rocket test may fall short of representing the faster speed and higher energy of a meteor hurtling into our atmosphere, but it does suggest that even if the outside of a meteor was scorched, genetic material in certain places on the meteor could survive higher temperatures than scientists had previously realized and make it to Earth.

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