----- Forwarded message from "F. James Rohlf" <[email protected]> -----
Date: Sun, 1 Dec 2013 07:51:01 -0500
From: "F. James Rohlf" <[email protected]>
Reply-To: [email protected]
Subject: RE: cladistic vs phenetics method
To: [email protected]
I agree and would add that I don’t think of a statistical method being either
phenetic or cladistic. A clustering method such as UPGMA just does its thing.
The user may choose to interpret the results as an estimate of a phylogenetic
history or just as a useful way of sorting OTUs into hierarchical sets based on
the available data. It is true that when estimating a phylogeny or creating a
classification based on overall similarity researchers will tend to use
different methods but there is overlap (e.g., an unrooted additive tree can be
quite useful for revealing near neighbors in a multivariate space and a UPGMA
dendrogram can be an estimate of phylogeny if certain assumptions are made).
However, with the long and often heated history of abuse of these terms it is
easy to slip and be careless in the usage of these terms but one should try to
avoid that because it can lead to confusion.
----------------------
F. James Rohlf, John S. Toll Professor, Stony Brook University
The much revised 4th editions of Biometry and Statistical Tables are now
available:
http://www.whfreeman.com/Catalog/product/biometry-fourthedition-sokal
http://www.whfreeman.com/Catalog/product/statisticaltables-fourthedition-rohlf
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> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]
> Sent: Sunday, December 01, 2013 3:37 AM
> To: [email protected]
> Subject: Re: cladistic vs phenetics method
>
>
> ----- Forwarded message from Joe Felsenstein <[email protected]> -----
>
> Date: Fri, 29 Nov 2013 10:09:44 -0500
> From: Joe Felsenstein <[email protected]>
> Reply-To: Joe Felsenstein <[email protected]>
> Subject: Re: cladistic vs phenetics method
> To: [email protected]
>
> Shobnom Ferdous asked:
>
> > We use cladistic method, some people use phenetics method for
> > answering different questions. What do you think the major differences
> > for those two methods, what can cladists do using phylogenetic method,
> > that is not done by phenetics methods? Any thought or comments is much
> > appreciated.
>
> Please pardon me making one of my rants.
>
> 1. My own opinion:
>
> It depends on what you mean by "cladistic" as opposed to "phenetic methods".
> If the question is how to make a classification, these adjectives are
> perfectly
> straightforward descriptions of approaches.
>
> But if you are talking about different methods for inferring phylogenies, or
> methods for making inferences about evolutionary processes, one simply should
> not describe some methods as "cladistic"
> and some as "phenetic", because they're not about classifications.
> If one tries to use these labels, one ends up describing parsimony as
> "cladistic",
> distance methods as "phenetic", but then likelihood and Bayesian methods get
> described as one or the other, depending on who is doing the describing. Or
> maybe they are cladistic on even- numbered days and phenetic on odd-
> numbered days. Which just goes to show that something is wrong with those
> designations in this case.
>
> 2. Everyone else's opinion:
>
> They get mixed up between the two tasks (classification and evolutionary
> inference) and end up taking an interesting discussion of inferring
> evolutionary
> history, or inferring evolutionary processes, and turning it into an
> exceedingly
> useless discussion of classification. They also tend to (if they are
> "cladists")
> declaring some methods of inferring phylogenies to be fundamentally wrong
> because they are not "cladistic". Or if the people are pheneticists, they
> tend to
> equate any study of phenotypes with being a validation of a phenetic approach
> to classification.
>
> So the issue is really: what is the question? If the issue is not
> classification, can
> you ask the question again without using the adjectives "cladistic" or
> "phenetic"?
>
> Joe
> ----
> Joe Felsenstein, [email protected]
> Dept. of Genome Sciences, Univ. of Washington
> Box 355065, Seattle, WA 98195-5065 USA
>
> ----- End forwarded message -----
----- End forwarded message -----
