When scientists first decoded the human genome a decade ago, they expected a fairly straightforward set of directions for making you or me.
What they found was quite different. Most of our DNA doesn’t directly code for anything.
The name that attached to it was “junk DNA.”
(Oscar the Grouch lives in a junk can but has recently become a staple character in fancy birthday cakes, as in this example.)
Well, as your momma probably told you, God don’t make no junk.
Some European scientists have recently abandoned the junk designation entirely, preferring to call for the study of the whole genome under the name hologenomics.
In just the last year we have found that “junk DNA” has a vital role to play in evolution, that proteins can “cut and paste” it into a form that actually does code, and now that its byproducts can help diagnose certain types of cancers.
Scientists have even seen how cod turned some junk DNA into a form of evolutionary antifreeze that allows the fish to survive in cold polar waters.
The same sorts of discoveries are being made with plants. So-called “junk” makes a genome more sturdy, and allows for rapid evolution of a species in reaction to stress.
Take rice, for instance. Ever since the first rice DNA was fully sequenced, in 2005, Chinese scientists have been puzzling over the vast amount of “junk” in it. It’s a vital element in creating evolutionary novelties, and this can be used to make rice that is more disease-resistant.
My guess is that “junk DNA” is going to be a big part of the medical frontier for the decade just started.
Here is what I think we’ll find. Evolution proceeds along something like the scientific method, but unsuccessful experiments are not discarded. Instead they’re encoded for possible use later. The more extra parts your DNA has the more it can resist change. And the longer a species exists the more resistant it becomes.
How you think dinosaurs turned into birds, anyway?
