[Taxacom] SUSPECT: Re: Molecules vs Morphology‏

[Jason Mate]

Weighing was very popular but is not very objective. Introducing "theory" (a researchers own particular bias on how that group should have evolved) into the search is so rife with risks that if one gets the results they were looking for the next question should be how much of it is based on data massaging. Besides the analysis of "molecular" data is not theory free either or phenetic as John claims:i.e. weighing according to codon position, according to the kind of aminoacid change, the location in the protein, etc., etc. is commonplace. The point should be if the character states of two different taxa belong to the same homologous site/structure, period. Yes the complexity of a sequence is much less than many morphological characters, but arguing this accross assumes that morphology is more than the genome which begs the question of where this information is hidden.

Jason
> Subject: RE: SUSPECT: Re: [Taxacom] Molecules vs Morphology‏
> Date: Sun, 16 Aug 2009 16:16:42 -0500
> From: Richard.Zander at mobot.org
> To: jfmate at hotmail.com; taxacom at mailman.nhm.ku.edu
> 
> Molecular data is commonly not weighted phyletically, just like phenetics. To some extent, then it is "automatic classification" and "theory free" just like phenetics. How to weight DNA sites is, of course, nothing I can contribute.
> 
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> 
> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Jason Mate
> Sent: Sunday, August 16, 2009 3:34 PM
> To: Taxacom
> Subject: SUSPECT: Re: [Taxacom] Molecules vs Morphology‏
> Sigh, not fair to use the "molecular data is phenetics" card when pressed into a corner. Because then your argument 
> falls into a data quality issue which as I have been trying, unssuccessfully it seems, to point out, is a moot point as 
> the distinction is not there. A large number of characters is a large number of characters. Mind you, I don´t mean that a sequence that is 1000bp long with 100bp which are variable and "informative" is better than 50 morphological characters.
> Obviously a single point mutation cannot have the same weight as a morphological character (OK, some of the morphological 
> characters out there are probably as weak but lets simplify the argument). However, if I have 50 genes, both nuclear and
> mitochondrial, and they point one way, and the morphological data is in conflict... lets just say the morphological dataset 
> needs some explaining.
> 
> 
> Best
> 
> Jason
> 
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