Proof that life didn't originate on Earth?

[Colanth]

First, the earliest life probably didn't include DNA.  Some kind of nucleic acid, probably, but probably not DNA.  So by the time we got the simplest DNA, we already had a complex genome.

Second, there's a thread with a link to a youtube video of how life probably originated.  Look for it.  Purely physical (and chemical) processes could have easily created life.