Figure 3

Left: Execution of the BUILD algorithm on the set of given four triplets. This example requires two iterations of the algorithm (delimited by a dotted line). At the first iteration, the triplet graph contains three components, leading to a polytomy with three leaves. The algorithm then iterates on the component {a₁, a₂, c₁}, which terminates the supertree reconstruction procedure. Notice that the gene tree of Figure 1, which is compatible with the four triplets, is not a resolution of this non-binary tree; Right: A variant of the BUILD algorithm, with the triplet graph components grouped into bipartitions - in this case leading to a fully resolved tree. This tree is actually the gene tree T of Figure 1.