Just like in our DNA...

[Martijn Faassen]

Greg Ewing <greg.ewing at compaq.com> wrote:
> Guido van Rossum wrote:
>> 
>> I don't know that the difference would be in the non-coding DNA, though.

> Seems plausible enough to me. Most of the basic building
> materials, metabolic processes, etc. are much the same from
> one species to another. It's the "control structures", however
> implemented, that are going to decide what shape the organism
> grows into. If the control structures turn out to reside in
> the non-transcripted DNA, it may well be true that most of the
> differences between species are in there.

I don't think it works like that. Genes (pieces of DNA) turn each other
on by being transcribed into proteins (who do the real work turning on
and off other genes). I think it's also possible for genes to be influenced
by RNA directly. These are control structures, along with the many complicated
enzym constructs you find in cells.

Morphogenesis, what shape a creature will grow into, happens through the same
process. It's still not completely understood, I think, but in some cells
genes are activated or turned off, making the cells behave differently, forming
a different tissue. This way structures grow.

They've identified genes in Drosophila (fruit fly) DNA that regular this
morphogenesis. By messing around with you can get flies that have legs in
the place of their eyes or other horrible things.

The trouble with junk DNA is that it doesn't seem to code for *any* active
RNA or protein in the cell. So it's unlikely junk DNA consists of
control structures.

Regards,

Martijn
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