Re: [asa] Re: "junk" DNA

From: David Campbell <>
Date: Mon Jun 18 2007 - 13:22:30 EDT

> This is a good point. If ID = "no common descent," then yes, it seems that
> "junk DNA" would be a problem -- though given the snippets I've seen from
> reviews of Behe's current book, it seems hard to claim that "ID = no common
> descent."

It seems pretty easy for folks at the Wells/Johnson/Ross end of ID to
make that claim, as they do it a lot. If ID advocates wanted to state
"We have a range of views on common descent", in keeping with their
"big tent" self-description, it would be internally consistent, but as
is each claims that ID represents the position he is personally
advocating at the moment.

The fact that an onion has lots more DNA than us could conceivably be
excused by the very different biology of onions and humans. However,
closely related and apparently biologically similar organisms can have
vast differences in the amount of DNA. At one point (don't have an up
to the moment reference) the record for most DNA per cell was an
amoeba; a close relative had an ordinary DNA level. Corn has double
that of most wild relatives; wheat has triple. Conversely, some
organisms (especially those with short life spans) have highly reduced
total DNA yet have functional genomes.

The discovery behind the current articles is that a number of bits
with apparently important functions vary greatly between organisms.
This is in accord with a model that assumes that whatever bits and
pieces happen to be on hand have been put to use.

An underlying difficulty is that there is not a single, tightly
constrained model for evolution nor for non-evolutionary design.
Rather, evolution could proceed in several directions using a variety
of mechanisms; an intelligent designer could do almost anything. A
very common line of argument for ID, flood geology, etc. is "Here is a
problem for conventional view x, therefore my model is correct." In
reality there are usually alternatives within the conventional
approach. Also, to accept the alternative model would require
demonstration that the alternative provides a better prediction of the
observed evidence than the conventional. (It is of course possible
that neither are good). Finally, if an alternative model works better
in a particular situation, this does not prove that it totally
replaces the conventional view for all situations. It's also
necessary that the purported problem, representation of the
conventional view, etc. are all accurate. Paul Nelson, in his debate
here with Michael Shermer, claimed ID simply had noted some
interesting anomalies and did not have an alternative model. It's OK
to do that, but that is not the picture of ID as proven alternative
model that is being marketed to the general public.

This argument does work in the opposite direction-it is impossible to
rule out a role for some form of intelligent action. Again, "not
disproven" is a much weaker claim than is made about ID in most
popular venues.

Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
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Received on Mon Jun 18 13:22:45 2007

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