Molecular taxonomy: on way out?

John Grehan jgrehan at SCIENCEBUFF.ORG
Thu Jul 21 14:18:28 CDT 2005

> From: Richard Jensen [mailto:rjensen at]
> Sent: Thursday, July 21, 2005 11:41 AM
> To: John Grehan

Pheneticists did not
> claim
> that more characters yielded better phylogenies.  What pheneticists
> claim was that more characters provided a better classification. 

Ok - although as I read the literature it seemed to amount to the same

As is obvious from your comments, systematists don't agree
> on which characters are valid for examining a particular group.

In that context DNA sequences are also arbitrary since there is no
single method for their designation and analysis.

> And, as others have pointed out, determining polarity a priori is not
> necessary.  If you have a unique minimum length network for your OTUs,
> that polarity does is give you the location of the root that is
> with that network and your data.  It will not change the topology of
> network.

As I keep pointing out, it is the data itself that is different between
molecular methods in which there appears to be no way to know which
sequence is primitive or derived other than how the algorithm
manipulated the total data, and morphological methods where the data is
limited to demonstrably derived states.

John Grehan

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