>I must agree with John.  Some folks seem to think that DNA
>automatically gives definitive objective answers whereas other
>criteria are more subjective. On the contrary,  when the DNA of two
>morphological forms is profiled, some human being still has to look
>at those two profiles and make a subjective decision as to whether
>the DNA is sufficiently different to warrant separation at the
>species level - exactly the same kind of subjective decision that
>has to be made when using only morphological characteristics.
>Therefore DNA is indeed just one more characteristic that can be
>referenced in making such decisions.  DNA can be very useful though
>in cases where two forms are quite distinct morphologically, yet are
>still closely related genetically - or where two forms are quite
>similar morphologically, but are not actually closely related.

Absolutely. The same goes for cladistics... choice of characters as
well as weighting is subjective.

Methods are just TOOLS. None is a be-all. No one is better than any
other. All are important. They can support one another, in which case
confidence in the outcome is good.

In a recent case someone used DNA work to show that sperm whales are
closely-related to mysticetes (baleen whales) rather than odontocetes
("toothed" whales), and the evolution of which to have been
comparatively recent. This was shown to be dead wrong by the fossil
record of sperm whales, which goes back at least to the late
Oligocene.
--
Andrew Grebneff
Dunedin
New Zealand
Fossil preparator
<[log in to unmask]>
Seashell, Macintosh, VW/Toyota van nut

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