Fwd: Re: More on the 'cladistics' of sequences
pierre.deleporte at UNIV-RENNES1.FR
Tue Jun 15 17:58:58 CDT 2004
>A 08:56 15/06/2004 -0400, John Grehan wrote :
>>The definition of phenetics posted by Tindall (below) conforms to my
>>understanding and use of the term phenetics I posted on TAXACOM even
>>though such usage was problematic for other contributors.
If things are such as you state, you should thus have stopped talking of
"phenetic characters" or "phenetic sequences", and talk instead of possible
phenetic analysis of the data set (overall similarity criterion for
comparing terminal taxa, not characters) versus possible cladistic analysis
of the very same data set. This is why your usage is problematic.
Otherwise, making use of all available (and relevant) data is not
particularly cladistic or phenetic, it is a logical requirement in
scientific explanation (don't discard evidence).
A possible distinction in the data sets could be that some pheneticians
don't care if some characters are not inheritable, while phylogeneticians
(cladists or otherwise) should logically use inheritable characters only
(plausible markers of common descent).
But you were always talking of polymorphism in character states in the
outgroups (the discussion revealed that tis was the very meaning of
"phenetic character" in your personal acception), inducing possible
ambiguity in polarization and consecutive rooting, hence it doesn't seem
that inheritability was your point when talking of "phenetic characters".
And it has been largely argued that rooting and optimizing a topology are
independent operations. If you don't believe this, try it yourself. It's
not a matter of "phenetic" or "cladistic" opinion, it's pure logics in
basic graph theory.
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