Scientists Say the 'SELEX' Cancer-Detection Method May Be the Key to Discovering Alien DNA
Star Trek has lied to you.
If at some point, human beings encounter an alien species, they almost certainly won't look like us, but with pointy ears and bad haircuts. They also won't be humanoid but green, nor will they have slightly lumpy foreheads. They probably won't have foreheads at all.
Much of our collective idea of what aliens must look like comes from the assumption that life on Earth is indicative of life anywhere else in the universe. This is false. Not only would life on another world probably not develop eyes and ears and fingers and toes, they probably wouldn't even develop a genetic code that looks anything like the DNA or RNA that exists in flora and fauna on our planet. We don't even know if other life forms would use the same kinds of molecules that are common on Earth.
So, considering that aliens will be so uncompromisingly alien, how would we even recognize one of these creatures if we were to come across one? If, say, the methane-rich moon of Titan contained microscopic life forms, how could we tell that what we're looking at really was alive?
A new paper, published in Astrobiology, has a potential answer. In order to detect exotic alien life, we may be able to use an existing technique for spotting life that's developing in weird ways within humans. Through the use of a cancer detection tool, we might be able to spot life forms that would otherwise go unnoticed.
SELEX, the Systematic Evolution of Ligands by EXponential enrichment, is a technique that's used for spotting the signs of tumors within the body. Synthesized nucleic acids are released onto a sample taken from a potential cancer patient, and if these acids bind to ligands within the sample, it's an indication that cancer may be present.
Imagine you're looking for a needle in a haystack - throw enough magnets into the haystack, and they'll start attaching to the needle, making your job easier (okay, in real life, the magnets would probably just stick to each other, but this is just an analogy!).
Scientists from Georgetown University suggest using nucleic acids on samples taken from different moons across the solar system - and, potentially, further afield, once our technology improves - to attempt to sequence any DNA or DNA-like structure of molecules. This would enable us to be able to figure out what weird combination of atoms an alien species might use for its genetic code, and could help us to positively identify life from another planet that otherwise might be hard to spot.
According to the paper:
"Without presupposing any particular molecular framework, this agnostic approach to life detection could be used from Mars to the far reaches of the Solar System, all within the framework of an instrument drawing little heat and power."
Considering just how weird and wonderful alien life might be, this could be our best possible chance to find other living creatures within our immediate vicinity. The only downside is that if there aren't any aliens on Titan, Europa, or other fertile locations throughout the solar system, we won't actually be able to determine whether this strategy for finding aliens will actually work.
It does make it difficult for us to win our ongoing interplanetary game of hide and seek if all the other players are invisible. That's just not playing fair.