another interesting datapoint in the C-value "paradox"
is the giant roundworm Ascaris lumbroides, an endemic
intestinal parasite that...[oops. I'm under orders not to
tell any more gross parasite stories in public ;^)].
Anyway, there's this big worm that carries a normal
metazoan complement of "junk" DNA in its germline
but throughs away most of it in its somatic tissues.
Sort of a metazoan analog of the micronucleus/macronucleus
sceheme in Ciliates. This would seem to me to weigh against
the notion that the "junk" in present simply because there
are not adequate mechanisms to get rid of it.
btw, I think it was Brenner who made the distinction between
junk DNA and trash DNA. You see, junk you keep; trash you throw out.
I cornered him after a seminar after a little too muc wine and
cheese (you know the grad school rule: if it's free- eat it)
and offered "litter" DNA as a term to describe the extracellular
sticky mess that DNA makes when eukaryotic cells lyse.
Lateral transfer of genes can occur when thrifty phagocytic cells
come to pick up the litter...