More on the 'cladistics' of sequences

Richard Jensen rjensen at SAINTMARYS.EDU
Tue Jun 8 12:12:42 CDT 2004

John Grehan wrote:

> Sure, but if you don't agree with me you don't have to comment or even
> read the emails. Better than imputing what's going on in my mind.
> John Grehan

I believe impute is the wrong word here.  I am simply deducing, based on the
statements you post, what you do and don't appear to understand about
cladistic methodology.  When someone makes simple statement that is factual,
and you reject it, then I can deduce that you either don't understand or you
are being a gadfly.

Richard Jensen wrote:

Uninformative characters are ignored because they don't provide any
information about sister-group relationships.  I don't have to be a
hominid systematist to take a look at a data matrix and tell you whether or
a character is informative.

John Grehan replied:

Only in the context of the data matrix. Whether the characters are
really any good is another matter.

It has nothing to do with the data matrix.  A character that is identical in
all taxa in the analysis is uninformative and characters that are true
apomorphies are uninformative.  And this applies to both molecular and
morphological data.

Maybe I'll take your advice and just ignore your future postings; then you
can claim that you are not getting a fair hearing because no one will

With all due respect,

Richard J. Jensen              | tel: 574-284-4674
Department of Biology      | fax: 574-284-4716
Saint Mary's College         | e-mail: rjensen at
Notre Dame, IN 46556    |

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