Striking a balance, weighting and Cladistics

[Thomas DiBenedetto]

-----Original Message-----
From: Pierre Deleporte [mailto:Pierre.Deleporte at UNIV-RENNES1.FR]
>the notion of "no common mechanism" as recalled by Tom, ... i.e. the fate
>of a character on a given branch being completely independent from the
>fate of this same character on another branch of the tree of life. Recent
>developments by Mike Steel et al. nicely illustrate this by the
>mathematical demonstration that standard cladistics may be turned into a
>"maximum likekihood" approach... given that we assume "no common
>mechanism" for the evolution of the characters throughout the cladogram.

Very good point. Except that I would turn the explanation around slightly,
and say that the maximum liklihood approach devolves into cladistic
parsimony once it rejects the models that assume that there are common
causal mechanisms imposing predictable patterns on nucleotide
transformations in independent lineages.
-tom