polarized and unpolarized
Pierre.Deleporte at UNIV-RENNES1.FR
Mon Jan 14 18:48:24 CST 2002
At 17:02 09/01/2002 +1000, Larissa Vasilyeva wrote:
>2. He [Pierre Deleporte] wrote that different states are given a
>different weight, but, actually, states of the same character are of equal
>weight since 'weight' of a character means its position in a hierarchy.
In fact I wrote:
"In phylogenetic inference, ordering characters is a coding procedure
consisting in giving a different weight to changes between different states
of a character".
The key word is "changes". I was speaking of weight of transitions between
character states, i.e. weight of "steps" for parsimony analysis, but
neither "weight of characters" nor "weight of character states" properly.
> (If two genera differ in some character, and one genus possesses a
> primitive state of this character, while another genus has an advanced
> state, one can trace a phylogenetic line but both states are equal in
> level, consequently in weight).
I did not mean this at all, but "weighting changes" (steps). Character
ordering, in cladistic jargon, consist in giving increasing weight to steps
between character states more distant in the "order" (=unpolarized sequence
"Unordered" characters mean that for such characters all changes (= steps)
between any two states are given equal weight for calculating tree length.
Talking of "character weighting" instead of "character steps weighting" may
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