dcameron at mason1.gmu.edu (Don B Cameron) writes:
>I think junk DNA is where genetic memory is stored.
>The classic dogs spinning in circles (to mat down ancient
>prarie grass) before lying down comes to mind.
My understanding of "junk" DNA is that it consists of DNA
that is not expressed, eg, pseudogenes, cDNA which have
no preceeding promoter regions, so the information never
gets transcribed into mRNA, hence, never translated into
protein. As such, I don't see how "junk" DNA could be
responsible for any observed behavior. Only genes which
have gene products can effect behavior. Furthermore,
"junk" DNA does not have strong selection criteria placed
on it, so it is free to mutate. It would thus preserve
genetic memory with less fidelity than DNA which is needed
for the organism's survival. The purpose of "junk" DNA,
as I understand it, is to provide a reservoir of elements
which can be used by the organism for creating new genes.
Any genetic memory an organism has would have to come from
part of the genome that gets expressed.
Rick
--
Rick Graul
graul at netcom.com