McClade problem

Karen Hughes khughes at utk.edu
Sun Apr 11 15:40:59 EST 1999


I have a problem with McClade that I can't resolve.  

Is it possible to identify the number of character changes on each
branch in a tree, the sum of which should be the tree length?

I have tried  "Trace all Characters" together with the "trace all
characters options" but in the tree window, the tree length does not
correspond to the number of changes shown by the Trace all Characters
option (show bar for each change).  I have tried the "Options for all
changes calculations" and none of these correspond to the actual tree
length.   I have tried a sample data set with a tree length of 3 to test
this out and the trace all characters option shows  no character changes
for the single most parsimonious tree, even though the tree length is
indicated as 3.  I need to create a tree in which the branch lengths
accurately reflect the steps which comprise the tree length and can't
figure out how to do it.  Can anyone help?

My test data set is 
Tax1  1,1,1
Tax 2 1,2,2
Tax 3 1,2,3
The tree length should be 3

Karen Hughes
University of Tennessee
khughes at utk.edu




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