mes at zoo.toronto.edu
Thu Aug 24 22:32:58 EST 1995
In article <41hlip$du1 at mserv1.dl.ac.uk> Javier Quintero Vazquez <bnjquint at usc.es> writes:
>Can anyone tell me:
>a.-In your opinion, the transition/transversion rate that would be used
>in DNADIST program to the Cytochrome B sequence of fishes.
Ummm..... in the first place I would argue that you should not use distances
as they violate triangle inequalities and assume constancy. Second,
estimates of TV:TS are usually between 1:2 and 1:10 I think. If you
don't have a good way of telling... do you really think you should just pull a
ratio out of the sky?
>b.-Previously, can I expect many differences between: a tree building with
>distances based methods/a tree building with parsimony/cladistic methods.
The distance-generated tree will have _no_ logical basis, whereas
the parsimony-generated tree will have. In the distance tree you will not
be able to reconstruct evolutionary changes whereas in the parsimony
tree you will.
Mark E. Siddall "I don't mind a parasite...
mes at vims.edu I object to a cut-rate one"
Virginia Inst. Marine Sci. - Rick
Gloucester Point, VA, 23062
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