Supertrees are phylogenies (rooted evolutionary trees) assembled from smaller
phylogenies that share some but not necessarily all taxa (leaf nodes) in common.
Thus, supertrees can make novel statements about relationships of taxa that do
not co-occur on any single input tree while still retaining hierarchical
information from the input trees. As a method of combining existing phylogenetic
information, supertrees potentially solve many of the problems associated with
other methods (e.g., absence of homologous characters, incompatible data types,
or non-overlapping sets of taxa). In addition to helping synthesize hypotheses
of relationships among larger sets of taxa, supertrees can suggest optimal
strategies for taxon sampling (either for future supertree construction or for
experimental design issues such as choice of outgroups), can reveal emerging
patterns in the large knowledge base of phylogenies currently in the literature,
and can provide useful tools for comparative biologists who frequently have
information about variation across much broader sets of taxa than those found
in any one tree.