Just like in our DNA...

[Tom Loredo]

Michael Vanier wrote:
> 
> Actually, yes, I know something about junk DNA (I have a degree in
> molecular biology).  To the best of my knowledge (please correct me,
> anyone, if I'm wrong) no one has ever proved that so-called junk DNA serves
> no function whatsoever, although it isn't transcribed into proteins --
> e.g. it may have some role in maintaining the structural integrity of
> chromosomes during cell division etc.  

I don't know much about junk DNA (being an astronomer rather than a
biologist!), but we happened to have a physics colloquium this week
on yeast DNA that focused on this stuff.  It seems "junk DNA" is
now being called "noncoding DNA"---the part of the DNA that doesn't
code into proteins.  However, according to this talk, it is now
believed that at least some of this DNA serves a critical function
in determining under what situations various bits of coding DNA
are expressed---chemicals bond to upstream noncoding DNA and trigger
the transcription of the coding parts.  As already noted in the
thread, lower organisms tend to have a much higher ratio of
coding to noncoding DNA; but this may have more to do with them
being simpler (single cells rather than multicellular with different
cells needing to express different coding genes) and thus not
needing the extra control function of the noncoding DNA.

The talk was entirely on use of computational physics methods on
trying to identify the "code" of noncoding DNA; this is apparently
a major area of DNA research right now.

Peace,
Tom Loredo