Wednesday, November 7, 2007

Message in a Double Helix


Just about every paragraph of Bill Bryson's excellent 478-page A Short History of Nearly Everything contains a nugget of thought-provoking science fact or historical trivia. (Perhaps that's why it took me 3 months to finish it.)

Take the notion of junk DNA, for example. As much as 97 percent of our DNA is made up of instruction sets that do not have any discernible function and that are not involved in human reproduction.

Such an extremely low signal-to-noise ratio seems odd -- especially if one takes the traditional view that DNA exists as coding mechanism for reproducing humans. Why is there so much noise in such an important information system?

The question Bryson dares his readers to ponder is this: What if the important information is actually contained in the 97 percent of DNA that we classify as "junk" because it's not about us? What if humans exist simply as a mechanism for reproducing DNA that has other purposes?

Bryson puts it this way: "Most of your DNA is not devoted to you but to itself; you are a machine for reproducing it, not it for you."

This got me started thinking along the lines of a plot background for a science fiction novel. Suppose you're an omnipotent being. What would you do if you wanted to send a message 3.5 billion years into the future? How would you maximize the chances that your message would still be around after such a long amount of time? One option might be to create what we now know as "life": A self-perpetuating messenger, with survival and reproduction as its strongest instinct, that carries the message encrypted within its genetic code. (Encrypted data, as we all know, appears as "junk" to anyone who doesn't have access to the encryption key.)

It's a tantalizing idea for a science fiction novel -- and maybe I'll get around to writing that novel one day. Interestingly, scientists have found that the genetic code of rats, mice, and humans share many identical chunks of "junk" DNA -- lending support to the idea that all lifeforms on Earth are simply messengers carrying a hidden payload of occult data.

Makes one wonder what the message is -- and what will happen to life on Earth when that message is finally read by its intended recipient.

(That's it for today's foray into the Twilight Blog Zone. We will now resume our regular programming.)