"Robert Karl Stonjek"  wrote in message
news:c9qala$1f44$1{at}darwin.ediacara.org...
> Life goes on without 'vital' DNA
> Sylvia Pagán Westphal, Boston
> ...
> To find out the function of some of these highly conserved
> non-protein-coding regions in mammals, Edward Rubin's team at the Lawrence
> Berkeley National Laboratory in California deleted two huge regions of
junk
> DNA from mice containing nearly 1000 highly conserved sequences shared
> between human and mice.
>
> One of the chunks was 1.6 million DNA bases long, the other one was over
> 800,000 bases long. The researchers expected the mice to exhibit various
> problems as a result of the deletions.
>
> Yet the mice were virtually indistinguishable from normal mice in every
> characteristic they measured, including growth, metabolic functions,
> lifespan and overall development. "We were quite amazed,"
says Rubin, who
> presented the findings at a recent meeting of the Cold Spring Harbor
> Laboratory in New York.
>
> He thinks it is pretty clear that these sequences have no major role in
> growth and development. "There has been a circular argument that if it's
> conserved it has activity."
> ...
Very interesting.  These regions resist mutation, but they don't resist
wholesale deletion.  Many questions.  Do the resist mutation selectively,
or do they just not mutate?  Are they selfish DNA?  This one bears
watching.  I'm curious what happens when mice with the deletion are
bred with "wild" mice.  Both sexual selection issues and Mendelian
ratio issues are worth noting.  Or, does the deletion cause hybrid
inviability or infertility?

I wish I could see the paper.  The article says "nearly 1000 highly
conserved sequences shared between human and mice".  Does that mean
1000 different sequences or 1000 copies of the same sequence?  If the
latter, then it is not quite so interesting.
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