[Taxacom] Felsenstein lecture available on-line

Bob Mesibov mesibov at southcom.com.au
Wed Dec 3 16:18:57 CST 2008

I think I agree with part of Felsenstein's opening line in the abstract,
in that the molecular phylogenetics papers I read contain more verbiage
than they used to on the statistical uncertainties associated with the
published inferences.

(That might partly be explained by the fact that these days people look
at more exemplars at once, and partly by the fact that its now popular
to do separate inferences from different datasets, and then, what the
hell, concatenate the lot and do a combined inference.)

However, I don't think most phylogeneticists have gotten very far from
their interest in coming up with a single phylogeny. They're still
chasing that One True Tree of historical relationships, and hope to see
glimpses of the Grail through the clouds of statistical uncertainty.
They often write about 'phylogenetic signal' vs. noise, as though there
were only one signal in the molecular data.

I don't think that's a reasonable way of looking at molecular
phylogenies. Surely there are many signals in molecular data, because
every gene (or part of a gene, or part of a not-really-a-gene sequence)
might have a different history, and just to make things messy, not all
of those histories can be represented as a bifurcating tree.

There's a nice sub-text in Richard Zander's posts, too, suggesting that
long and close experience with a group puts you in a better position to
make judgements about evolutionary relationships. That certainly runs
counter to the notion that any raw graduate student can grab a few
exemplars, get a few sequences out of them and generate a credible
history relating those exemplars - within a few months, at most.
Dr Robert Mesibov
Honorary Research Associate
Queen Victoria Museum and Art Gallery
and School of Zoology, University of Tasmania
Home contact: PO Box 101, Penguin, Tasmania, Australia 7316
Ph (03) 64371195; 61 3 64371195
Webpage: http://www.qvmag.tas.gov.au/mesibov.html

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