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In a message dated 6/16/03 1:18:33 AM EST, email@example.com writes:
<< Invalid argument. Because something happens in one lineage doesn't mean it
have happened in others. For example, just because no other vertebrates have
rostral bones does not mean that ceratopsians could not have had them.
At any rate, other types of homeotic shift have been observed. And it's been
shown that digit identity and number are developmentally independent. >>
If a "frame-shift" can be shown to happen from time to time in other
lineages, then you have a much stronger case for its occurrence in the
lineage. If, however, a "frame-shift" is an artifactual construct dreamed up
to account for an annoying discrepancy in a cladogram, unknown anywhere else,
then it is just another junk hypothesis, something cladists dredge up to
explain why their cladograms don't seem to accord with reality.