UVP Life Science User Manual
Page 152
LS Software User Guide
138
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Weighted pair-group method centroid (WPGMC): This is identical to UPGMC except that the
number of items in a cluster is taken into account &endash; this may be useful when there is a
large variation in the number of items in the clusters.
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Ward’s method: This method differs from the others in that it uses an analysis of the variance to
calculate distances between clusters. An item is joined to a cluster if the joining results in a
minimum degree of variation within the cluster. This means that items will not get grouped into a
cluster simply because they do not belong anywhere else. As a consequence, Ward’s method
can lead to a large number of small clusters.
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Neighbor joining: At each stage of clustering the total branch length is minimized. The distance
between two items is approximately the sum of the branch lengths between them. The trees are
not right-aligned and branches can have negative values. Details of the method can be found at
http://www.icp.ucl.ac.be/~opperd/private/neighbor.html