Thursday, October 21, 2004

Then Again, Maybe it's Not Junk...

On the other hand, Scientific American has this article up arguing that much of the junk DNA does play a vital role in embryological development. Sadly, the full article is only available by subscription, but the headline and subhead say it all:

The Hidden Genetic Program of Complex Organisms:
Biologists assumed that proteins alone regulate the genes of humans and other complex organisms. But an overlooked regulatory system based on RNA may hold the keys to development and evolution

Of course, there's no contradiction between thie article and the news brief I mentioned in my last posting. It's only about two percent of the genome that codes for proteins. The rest is non-coding. It was only a small portion of this junk that was deleted in the mouse study reported below. It's entirely possible that some of the junk DNA serves a function, while some of it is, indeed, junk.

We should mention as well that finding some function for junk DNA does not imply that this DNA is not also an evolutionary vestige. As I have pointed out many times at this blog, vestigial and non-functional are two different things.


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