Manufactured data sets - was Re: Felsenstein versus Ockham?

David Orlovich d.orlovich at UNSW.EDU.AU
Wed Jan 27 09:27:12 CST 1999

R. Zander wrote:
>There is no evidence a priori that a data set
>species A 1 2 3 4 5 6 7 8 9
>species B 1 2 3 4 5 0 0 0 0
>species C 0 0 0 0 0 6 7 8 9
>with species A and B sharing characters 1-5 must be more closely related
>than species A and C sharing characters 6-9.

It seems to me that if a data set was not clearly able to "give up" its
phylogenetic secrets then the simple answer is to get more data.  Isn't the
underlying principle that evolutionary history IS going to be reflected in
the evolution of characters and it's our job to test their homology by
analysis of as much data as necessary to give that answer?  To manufacture
a data set like the one above is akin to asking "how would be deal with a
mammal (sp. B), a bird (sp. C), and a mammal with feathers (sp. A)? - or
for that matter, a unicellular procaryote, a chicken and a bacterium that
laid eggs!".  If the data set above is the entire one for the imaginary
organisms, then it won't ever exist and therefore doesn't matter, and if
it's a partial character set for another set of imaginary organisms, then
someone needs to look for more characters.

Of course I might have got the wrong end of the stick completely and I'm
sure someone will tell me!

David Orlovich.

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