Publishing on human origins

[John Grehan]

Peter Werner raised some very germane questions. My comments as follows:

>My first question would be how effectively did the paper you are
>talking about deal with the whole question of why the morphological
>evidence and the molecular evidence are at odds, and what may be wrong
>with the particular molecular sequences or phylogenetic techniques that
>is leading to aberrant conclusions.

This was not addressed as it was not the purpose of the paper. However, the
editors evidently did not want that to be addressed or they would have made
that suggestion.

>If the papers argument is,
>effectively, "The molecular data don't agree with my interpretation of
>the morphological data, therefore the molecular data are wrong," then I
>can't blame Natural History for not taking the article.

No that was not the paper's argument (see comments in other recent posting).

>The author maynot have molecular data to support his or her position, but
>the author
>must still provide some explanation as to how others have found
>molecular data that seemingly falsify the author's conclusions.

Basically I think it goes the other way around. What have the molecular
systematists demonstrated (not claimed) to show that molecular data
necessarily have any priority over morphology and that DNA sequence data
has any necessary match with phylogeny (So far all I have found are claims
for justification in terms of a molecular sequence matching morphological
trees! For example there are molecular trees supporting the gibbon as a
closer relative to humans and African apes than orangutans and this is
rejected because it does not conform).

John

>I'm far from an expert on primate evolution or vertebrate morphology in
>general, but my experience with taxonomy has been that often people who
>disparage molecular data because "it contradicts the morphological
>evidence" are simply

That is possible. One could make the converse argument about molecular
systematists. I'm not sure whether this is all that enlightening in this
case. In my situation I was not attached to any particular hypothesis when
I started looking into the matter.

>too attached to one particular evolutionary
>hypothesis to consider that there may be other valid interpretations of
>which morphological traits are more primitive, which are more derived,
>and which are homoplasies.

This is of course possible, and there are ways to approach the
morphological characters to test out options. In the case of many hominoid
systematic papers it is neither easy or in some cases even possible because
character documentation and description is abysmal.

>  Eventually, some kind of congruence should result.

I reagard that as the open ended question. What is some kind of congruence
between DNA sequences does not result? Should there necessarily be
congruence between morphological cladistic characters and DNA sequences?

My three cents

John Grehan