I would like to add that possessing extra copies of information has *potential*
value, in that one copy could later be altered while 'the original' remains the
same or gets altered in different ways. Like in morphology, where we see
identical segments becoming distorted and losing their primitive symmetry.
It would be fascinating if we could tie repeated segments of DNA to repeated
morphological structures; all that 'redundant' DNA, those repeated sequences,
could be the basis for the primitive morphology of many repeated identical
segments. But I think the common--and probably correct--view is that repeated
structures can be generated by re-using the same DNA sequences. Yet this
view does not explain how so many different segments within an organism
can develop such refined and persistent distortions; this would seem to put
a great burden upon the processes that regulate development; that is, it
seems easier to grant that each segment has its own evolved variation
of its morphology-generating DNA.
Sorry if this is a little weird; I'm just really interested in the nuts and
bolts
of evolution and development. I'm stretching the discussion a bit from
repeated chromosomes to repeated DNA segments in general, for one
thing, but it's all DNA.
--Cliff Lundberg ~ San Francisco ~ cliff@noe.com