Phylogenetic Tree Reconstruction: Geometric Approaches - Mathematical Concepts and Methods in Modern Biology - page 325

FIGURE 10.7
Pictorial representation of successive steps in the Neighbor-Joining Algorithm.
From http://en.wikipedia.org/wiki/File:Neighbor-joining_7_taxa_
start_to_finish.png .

The NJ Algorithm is predicated upon the Q -criterion in the sense that if one starts
with a tree metric, then the minimum value of Q gives a cherry, so if one is looking
to build a tree from an arbitrary dissimilarity map, one might likewise try calculating
the Q -values, and hope it works. As it turns out, this is practically and mathematically
effective, yielding an algorithm with running time O

n 3 ( ) [ 24 ], but in its current