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According to eyewitness accounts of 'aliens' we have a Universe teeming with extra terrestrial neighbours of all shapes, sizes, and colours. Yet despite the pictures, reports, testimonies, and video footage, we have no definitive proof of life anywhere else other than the rock we call the Earth. We've sent probes to other planets, but still nothing. ET is either good at hiding, doesn't exist, we're looking in the wrong places, or we haven't yet developed the technology to find alien life.
There are of course tantalising signs that planets may have once harboured life, such as the evidence of water on Mars. Water is fundamental to life as 'we know' it, but this isn't as satisfactory as finding proof. Chemical signatures such as the presence of methane have been detected, but these results are ambiguous as it's not just biological processes that produce the gas. Supposed fossils of alien microbial life are equally contentious.
There are many scientists who think that if there is life on another nearby planet, for example Mars, it will probably be microbial and exist just below the surface, where liquid water might be widespread.
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Prof Gary Ruvkun, a microbiologist at Harvard Medical School is hoping to send a DNA amplifier and sequencer to the planet Mars to find alien DNA. The project is supported by the space Agency NASA and labours under the title of the Search for Extraterrestrial Genomes (SETG). Ruvkun's gamble is that life on Earth and Mars shared a common heritage and therefore DNA on both planets should be roughly the same. Though others argue that if there is life on the red planet, it may have evolved independently.
The device is still in its developmental stages but alien DNA could be detected by first burrowing into the Martian soil, and collecting a soil and water sample. Ruvkun's creation would then mix the sample with a dye that fluoresces when it binds to DNA. Fluoresence would highlight the presence of DNA which could then be amplified. Ruvkun is not sure yet which technologies will be used to decode this DNA, but it could be something that emerges from the $1000 dollar complete human genome race.
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The scientists will amplify and analyse a gene called the 16S ribosomal RNA subunit. The reason for picking this gene is that it has barely mutated over the 4 billion years that life has existed on this planet. It therefore provides a useful tool to study evolutionary relationships between distantly related organisms.
Martian 16S ribosomal subunit RNA will be compared with sequences from organisms on Earth. There is a school of thought that Earth and Mars may have exchanged life some 3-4 billion years ago when large impacts threw lumps of each planet into space. If this happened then it would be expected that any Martian DNA would resemble an island species, distinct from mainland (i.e. Earth) DNA. If the genetic material appears to be too similar to each other then this could be evidence of contamination and not of ET.
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Ruvken and his team are hoping to bag a place on a future Mars mission scheduled for 2018. In the meantime the next few years will be spent road testing the technology in various locations on this planet that have Mars-like conditions, such as dry valleys in Antarctica.