http://www.newscientist.com/article/mg22430000.900 So you're an alien seeding primordial Earth with life. Like any creator, you sign your work. Now we may have found that signature – in the genetic code
MAXIM MAKUKOV has an idea. It's unorthodox; you might call it "out there". Makukov understands that. He knew he'd have his critics the moment he began to develop it. But it's there in the numbers, he says. And numbers don't lie.
A cosmologist and astrobiologist at the Fesenkov Astrophysical Institute in Almaty, Kazakhstan, Makukov says the numbers reveal that all terrestrial life came from outer space. Not only that, it was planted on Earth by intelligent aliens. Billions of years ago, the planet was barren and lifeless. But then, at some distant and unknowable moment, it was seeded with what Makukov calls an "intelligent-like signal" – a signal that is too orderly and intricate to have occurred ...
Unfortunately new scientist requires you to sign up, so I'll look around for a complete article on the subject but it's actually really brilliant
p.s. ib4 creationists come along and claim it's the work of God and refuse to acknowledge the fact it might actually be aliens that made us for shits and giggles.
Damn, as usual the internet is swarmed at the moment with creationist rants so I'll have to search a bit more carefully.