Tree of Life

30/10/02


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Table of Contents

PPT Slide

Tree of Life

PPT Slide

Problem: how to build the tree of life

Tree terminology

Nestings and triplets

Supertree

Some desirable properties of a supertree method (Steel et al., 2000)

PPT Slide

Aho et al.ís algorithm (OneTree)

PPT Slide

Mincut supertrees

PPT Slide

Collapsing the graph (Semple and Steel mincut algorithm)

Cut the graph to get supertree

My mincut supertree implementation darwin.zoology.gla.ac.uk/~rpage/supertree

A counter example: two input trees...

Mincut gives this (strange) result

Problem: Cuts depend on connectivity (in this example it is a function of tree size)

So, mincut doesnít work

What mincut doesÖ Öand does not do

Modifying mincut supertree

Uncontradicted information assume we have k input trees

Uncontradicted information assume we have k input trees

Classifying edges

Modified mincut

If no tree contradicts an item of information, is that information always in the supertree?

No! Steel, Dress, & B–cker 2000

Future directions

Author: Roderic D. M. Page

Email: r.page@bio.gla.ac.uk

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