A lot has been made recently about human survival and settlement in space. Russians are planning to build a human settlement on the Moon. Evidence of liquidized water was found on Mars. Matt Damon got stranded on Mars in this fall’s blockbuster The Martian and lived to tell the tale. It’s even been proven that crops from Earth could be grown and cultivated on a climate and environment like the one on Mars. But what about animals, our fauna brethren in the animal kingdom? Turns out, they don’t fare so well outside of our big, blue planet. Except for one, that is.
Tardigrades, colloquially referred to as water bears, are the only known animals that have survived the dark, cold vacuum of space. These indestructible little weirdos owe it to their genetics – a sixth of their DNA comes from foreign organisms. Researchers at the University of North Carolina at Chapel Hill sequenced the tardigrade’s genome to discover their unorthodox and fascinating genetic makeup. The water bear boasts a whopping 6,000 genes that don’t originate within the species.
Water bears can survive extreme temperatures (-272C to 151C) by weathering desiccation, or extreme drying. When they’re dried out, their DNA breaks up into small pieces and once rehydrated will repair. During this process, they absorb foreign DNA through leaky cell membranes. Known as horizontal gene transfer, which is the shifting of genetic material between organisms, water bears continue to evolve to help them withstand harsh environments. And there’s nothing harsher than space.
This amazing biological feat is quite common in the microscopic world. Other microscopic animals have been found to have large quantities of foreign genes as well. Humans can actually perform horizontal gene transfer as well, but in a much more limited scope with the aid of viruses and transposons. Still, the sheer magnitude of the tardigrade’s ability to shift their genetics is unparalleled. Because the species is known to suffer and survive desiccation, researchers believe they have evolved to the point where their genome can break down and integrate other genetic material due to a compromised nuclear integrity. This is similar to how scientists perform gene transfer and therapy using electroporation.
With the largest genetic complement of any known animal and the Darwinist ability to survive in space, tardigrades have the rest of the animal kingdom pretty much beat. If you’re planning on moving to Mars in the future and want a pet, you’re gonna have to settle for the microscopic water bear. They may not be super cuddly, or detectable to the naked eye, but at least they’ll survive the trip.