Figure 2From: Efficient error correction algorithms for gene tree reconciliation based on duplication, duplication and loss, and deep coalescenceThe NNI adjacency graph. (a) The tree G ¯ is obtained from G by pruning and regrafting subtree G v to the root of G. The vertex x ∈ V(G) is suppressed, and the new vertex above root in G ¯ is named x. (b) Two NNI operations NNI G' (z') and NNI G' (z) produce left-child G' l and right-child G' r of G' in X .Back to article page