Art Weil's question and the various lively answers have made an interesting
thread. The latest message, by Michael Reagin, supports some of Art Weil's
"wild" speculation. Yes, DNA sequencing is getting cheaper as time goes by,
and he even suggests that rapid DNA sequencing would be done using
mitochondrial DNA rather than whole-organism DNA. I doubt if Art would
mind! Art Weil's "black box" may be simplistic, but Michael Reagin shows
that the "Question Man" has indeed asked a reasonable question. (Of course,
anyone who saw the recent movie "Gattaca" has been wondering along similar
lines.)
 
My question has to do with the results. Suppose that Art has his black box
that rapidly and inexpensively sequences DNA. He finds that some snails
look almost alike but have very different DNA. Very well, DNA is the code
of life itself, so obviously these are different taxa
(species/genera/etc.), and he is inspired to search for the morphologic
details that might distinguish them in the field. More work is needed, but
no change in principles.
 
Then Art tests two snails that look very different but have almost
identical DNA. He tests many more snails and finds that these results are
consistent, not due to a mistake or to a single pathological individual. My
questions for Michael Reagin and other interested conchologists are: Are
these also separate taxa? Would the DNA specialist prefer to call them
different subspecies rather than different species or genera? Is the DNA
criterion the only one to be considered, or is morphology still considered
to be a valuable tool in taxonomy?
 
And what is a paleontologist supposed to do about it? Fossils usually don't
retain soft parts, much less DNA.
 
Andrew K. Rindsberg
Geological Survey of Alabama