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Re:phylogenetics, resuscitation



[danger:long-winded, possibly rambling monologue follows]
Plenty of people on this list seem to want some good solid paleontological
issue to discuss here (yours truly included). I think the recent posting
about dinoDNA being the ultimate and only solution to resolving the glaring
systematics problem with dinosaurs, and Jeffrey Martz's retort, is a good
start.

I fall in soemwhere between the two; probably more on LN Jeff's side of the
spectrum. I come from a neontological background like the dino-geneticist
(sorry, lost your name), and have a pretty good background in genetics. But
I also realize the limitations of the material to work on. The sad fact is
that DNA doe not sit well over several score million years, in amber, bone,
or whatever. Oxidation and other processes render it fragmentary quickly -
and the more fragmentary DNA gets, the less useful it is. (I'll stop right
here and assume that everyone on this list knows well that we'll never
resurrect dinosaurs a la J. Park)

In defense of dino genetics, I know there are good samples out there that
may well be useful to paleontology. Any DNA whose former owner can be
conclusively figured out is certainly very valuable (but truthfully, we
have to use the morphology-based phylogeny to find out who the owner was).
But workers must be wary lest further embarrassments like contamination
with younger DNA happen.

I have friends on both sides of the unfortunate genotypic/morphologic
phylogeny schism, and I don't understand why so often they say that their
side has the best tools for solving the problem in question. Really, what
tools are most useful for resolving phylogeny depend on the circumstances -
genetics is best with a good DNA sample and a respectable sample size -
i.e. in most neontological work. Morphology-based phylogeny is best with
less complete data - i.e. in most paleontological work. BUT, when the two
can be combined, compared, and results extrapolated therefrom, the analysis
gains alot of depth, and problems such as fragmentary DNA and convergent
morphology can possibly be illuminated. Yeah, it's alot of work, and
requires schooling in both sides of the "schism", but I think it's
self-evident that it can be beneficial.

I think the theme here is, narrow-minded convictions are bad. They just
cause problems in science - organismal vs. cellular level, macro vs. micro
evolution, paleontology vs. neontology, whatever! Science optimally is not
a cluster of isolated groups of disciplines - every field is inextricably
linked with others. Life is not a group of categories, names and numbers.
It's life and we're stuck in the dark like the three blind men and the
elephant.

Okay, enough with the koom-ba-ya "let's all be pals" stuff. What I
personally take from this is yes, get experience in genetics if you don't
have it. Yes, try to see the value of fields you're not too familiar with.
"True species identification"? Well, maybe with Drosophila or finches, but
I think for now we're stuck with what we've got.

As always with me, I hope no one sees my tone as condescending or
self-important. I put in my view of things and hope it catalyzes
discussion.

                        John R. Hutchinson
                  Evolving Evolutionary Biologist
                 Department of Integrative Biology
                University of California - Berkeley
                        Berkeley, CA 94720
                          (510) 643-2109

        "Thus, the student of adaptation has to sail a perilous course
between a pseudoexplanatory reductionist atomism and stultifying
nonexplanatory holism."         --E. Mayr, "How to carry out the
adaptationist program?"