A non-biodegradable cousin of DNA and RNA is being created. It cannot be broken down very easily by life on Earth because of its chemical make-up.
Ya, that will go over well:
"Do I think what these researchers have done is dangerous? Absolutely not. Do I think this is going to be dangerous in the near or even medium term? Absolutely not," Joyce said. "Still, are we treading into something risky here? It's synthetic biology, not a natural form of biology. Scientists have to pay attention here."
(
http://www.innovationnewsdaily.com/1064-move-dna-meet-durable-xna.html)
This reminds me of something, I can't quite remember what...
Oh right, grey goo! Shit.
http://en.wikipedia.org/wiki/Grey_goo