genetic vs morphological trace of phylogeny

John Grehan jgrehan at TPBMAIL.NET
Sat Apr 3 22:07:19 CST 2004


At 09:54 PM 4/2/04 -0600, Ken Kinman wrote:
>      Like Curtis, I find it hard to understand why anyone would suggest
> that evolutionary history leaves traces in morphology, but not the genome.

Who's making that assertion? Not me.

>It just doesn't make much sense if you think about it long
>enough.  Obviously not all genetic information is going to be
>phylogenetically informative, but some of it certainly is.

Agree completely!!!!

>It's just a matter of separating the wheat from the chaff (and the same is
>true for morphological data).

YES! (this is implicit in my suggestion that the only DNA sequences that
really matter are those that are correlated with the morphological
synapomorphies).

>If John hasn't been able to find molecular evidence for this hypothesis,
>then he should just keep digging for it.

I'm not the molecular geneticist. It will be up to others to 'dig' for it
IF the orangutan theory is correct.

>Arguing that it is probably irrelevant does not sit well with me at all.

It being genetic information? If so that's not what I said. What I have
said is that DNA sequence data may not necessarily always be correct in
predicting phylogeny (which is more or less what some others seem to be
admitting on TAXACOM, and which may be the case for the orangutan
relationship IF the morphological synapomorphies are a more accurate
predictor of phylogeny in this case). Unfortunately (perhaps) there is no
recipe for making a predetermined choice when DNA sequence similarities and
morphological synapomorphies are incongruent.

John Grehan




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