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Tuesday 30 October 2012

Martian DNA

Genomics maverick Craig Venter, life synthesiser and human genome cracker has conquered all Earthly summits and has set his sights on the next frontier: Mars.

Last week Venter revealed that he plans to send a DNA sequencer to Mars in his “biological teleporter” which will sequence any DNA it can find in the Martian soil and beam the data back to Earth. This eliminates the risky and potentially costly procedure of returning any physical samples to us in a useful form.

We’ve been searching for life on Mars for the past thirty odd years though, why haven’t we found it? And what makes Venter so sure he can succeed?

Venter is looking for something we’ve not looked for before, specifically DNA, what we know as the basis of all life on Earth. One thing we’ve learned recently about the building blocks of DNA is that the sugar that forms its backbone has been found floating around in space. Maybe they were thrown out from the fallout of asteroid collision that created our moon from primordial microbes on the Earth that was. Maybe they weren’t, but however they got there, there’s reason that they couldn’t settle on Mars and start making machines – life!

In the past, searches for organic chemistry on Mars have turned up nothing but ambiguity, most famously the Viking landers. These crafts found evidence of metabolic chemical reactions like those we see on Earth however the unusual content of the Martian soil may have corrupted the results of the experiments and any conclusions in favour of life have been more or less thrown out of the window. What Venter is looking for now is not simply reactions indicative of life but the chemical makeup of it itself.

Venter is not alone however in his search for DNA on Mars. A group at Massachusetts Institute of Technology called Search of Extraterrestrial Genomes (SETG) is working on building their own genome sequencer aimed at use on the red planet. SETG has divulged significantly more information than Venter has however. They are looking at identifying and sequencing both DNA and RNA (DNA’s older brother) using a next generation sequencing machine on a computer chip called Ion Torrent. SETG is seven years in the making and will search for genomic material made by something still living to anything synthesised up to a million years ago.

All of these plans are well meaning and incredibly exciting, but there’s every chance that if there is life on Mars, it’s still going to elude us because it’s not DNA based. Nevertheless if we do find DNA on Mars yet more weight is added to the hypothesis that life was seeded here and on Mars by passing asteroids. This would suggest that there might also be life in innumerable other locations throughout space, and how awesome would that be?

Living up to his reputation for arrogance and audacity, Venter has put forward that he has no doubt that there is life to be found on Mars. He says “there will be DNA life forms there”, this author for one hopes he is correct.