DNA analysis may be done on Mars for first time

In August 1996, molecular biologist Gary Ruvkun was about to reveal one of the biggest discoveries of his scientific career. His lab at Harvard Medical School had recently found a gene called age-1 that determines lifespan in roundworms. Their work offered the tantalising possibility that tinkering with molecular pathways might extend the lifespan of other organisms – and perhaps even humans.

Harvard sent out a press release and Ruvkun prepared for an onslaught of media attention. But it never came. Two days before his team's paper came out, scientists analysing a meteorite from Mars called ALH84001 made headlines worldwide. Then-US president Bill Clinton even got in on the announcement.

"My grad student leans in the door and says, 'They've just announced life on Mars,'" recalls Ruvkun. "That would really f--- us," Ruvkun replied, thinking his student was joking.

Scientists have since raised serious doubts about the existence of the purported fossilised microbes in the meteorite (see image).

But now, more than a decade after his work was overshadowed by news of possible life on Mars, Ruvkun has joined the hunt to find it. Moreover, he and his colleagues want to sequence its DNA.
Toehold for life

Today, Mars is a frozen, barren world. Ultraviolet light and energetic space particles stream in through its thin atmosphere, sterilising any life – at least as we know it – on its bone-dry surface.

But recent research suggests life might find a niche just below the surface, where liquid water could be widespread. The discovery of plumes of methane in the planet's atmosphere also hints at subsurface life, since some terrestrial microbes produce the gas.

Chemical signs of life can be ambiguous, but Ruvkun and his team hope to find its unequivocal signature by sending a DNA amplifier and sequencer to Mars in the next decade. They're betting that any life on the Red Planet shares an evolutionary heritage with life on Earth, and therefore contains a similar genetic code – a requirement that other scientists say is too narrowly focused, since Martian life may have evolved independently and therefore may have very different chemistry.

"This is a pure jackpot scheme. You either discover the most important thing for a long time, or you discover nothing," says Ruvkun, who in 2008 won the Lasker Award, an honour shared by 75 scientists who later went on to nab a Nobel.