Archaebacteria and the Three Kingdoms

Jonathan Badger badger at phylo.life.uiuc.edu
Tue Apr 12 00:18:29 EST 1994


Doug Eernisse <Doug_Ee at um.cc.umich.edu> writes:

>Am I missing something or does anyone else think this is a basic
>problem with not being able to say anything about the relative
>cladistic branching pattern of a three taxon statement? That
>is, without using rocks for an outgroup, and assuming each
>of these is more or less a cohesive group itself (which may
>not be true, for all I know).

Trees are based on sequences, not organisms. The "Tree of Life" can be rooted
by the use of paralogous genes such as the Alpha and Beta globins. All Alpha
globins are more closely related to other Alpha globins than they are to Beta
globins, even the Beta globin from the same species. So every species contains
its own outgroup -- neat, eh?



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