Transformed distance method UPGMA assumes constant rate Of evolution across all lineages-can lead to wrong tree topologies Can allow different rates of evolution across different lineages if you normalize using an external reference that diverged early.. e. use an outgroup Define dp =average distance a B d Between outgroup and all ingroups iD MiD )/2+d Now use d, to do the clustering basically just comes from the insight that ingroups evolved separately from each other ONLY AFTER they diverged from outgroupTransformed Distance Method UPGMA assumes constant rate Of evolution across all lineages - can lead to wrong tree topologies Can allow different rates of evolution across different lineages if you normalize using an external reference that diverged early…i.e. use an outgroup Define dD =average distance A B C D Between outgroup and all ingroups d’ij = (dij –diD –djD)/2 + dD Now use d’ij to do the clustering ..basically just comes from the insight that ingroups evolved separately from each othe r ONLY AFTER they diverged from outgroup