Putting the life back in science fiction

Unfortunately, the article is behind a paywall at the moment so you can only see the abstract, but PNAS just published a draft genome of the tardigrade Hypsibius dujardini.  Here’s the Yahoo news piece on the finding.

Basically, tardigrades are microscopic animals that are renowned for their ability to be frozen, boiled, desiccated, subjected to a vacuum on the outside of the space shuttle and so forth.  They’re the ultimate survivors among animals, and I’m pretty sure that every SF writer who thinks about putting astronauts in hibernation is thinking something along the lines of copying tardigrade’s toughness in humans through some futuristic technology.

But there’s an itty bitty catch.

If the draft genome is right (and there’s no reason to think it isn’t), tardigrades just took the record for having the most foreign DNA in their genome of any animal, about 16%, double the previous record holder.  They’ve got genes “derived from diverse bacteria as well as plants, fungi, and Archaea.”

My first thought was of Brin and Benford’s Heart of the Comet and the weirders (I still like that book), and then that ooh, massive horizontal gene transfer will take us to the stars!  Yay!  We get to go as gardens.

Then I read some more and found out that tardigrades’ toughness comes at a price: their DNA falls apart when they’re desiccated, and their cells get leaky as they rehydrate.  As a result, DNA from the surrounding environment gets taken up into their cells and, where it’s useful somehow, it gets taken into the tardigrade’s rebuilding genome.  Now bacteria do this all the time, so what’s unique here is that an animal has separately evolved the trick.  It’s one hell of a trick too, being able to repair eukaryotic DNA at that level and to usefully incorporate genes from wildly different organisms.  There’s a lot to be learned from these cute little water bears.

Still, this puts a whole different spin on putting people into hibernation to send them into deep space and to the stars.  It looks like tardigrades don’t have a magical way to avoid the damage caused by freezing.  Instead, it looks like they’re amazingly good at picking up the pieces afterwards and rebuilding themselves.  Presumably, that’s what we’ll have to learn to do (assuming it’s possible–tardigrades don’t have big brains),  if we want to turn people into corpsicles and back again without damage.  At the moment, the only methods we know of involve the use of either narrativium or handwavium, and both these elements are really unstable.