Table 2.

Steps used in hierarchical tree building.

1	Construct a ranked list of gene order distances starting with the shortest distances
2	Move down ranked list, forming NJ trees of increasing taxa number estimating reaching a NJ tree of all taxa
3	In turn, evaluate each tree formed starting with the smallest and moving to the largest
4	Keep trees consistent with all previously retained trees, while rejecting any new tree that is incongruent with a previously retained tree
5	Starting with those represented by the smallest gene order pairs, single taxa were added to the largest retained tree if their addition did not disrupt the existing NJ topology (second round of taxa addition)