there are so many possible coding schemes and the need for mutation proofing it will require some complex redundancy system, and we have no idea whatsoever what the original message would even look like, I'd have to guess the odds are low of finding such a thing. Even comparing multiple whole genome sequences from many individuals and looking for sequences the same in all is problematic since the "message" sequence would have accumulated different errors in different people.
Besides, perhaps the Medium is the Message
), I seem to remember reading somewhere that most of the "junk" in our DNA is made up of retro-viruses we picked up along the way. 
