Fig. 1.

Illustrative example of taxonomic assignment methods: LCA*, Majority and LCA². Node numbers indicate the number of annotations associated with each taxonomic position in the tree, and the double-circled node is the actual originating taxonomy. In a typical metagenomic assembly ORF, annotations can be variable, spanning a number of different positions in the tree. In this example, LCA² provides a conservative estimate, while the simple Majority method provides a specific taxon without very much support from the data. The LCA* tempers the Majority estimate by collapsing annotations up the tree in a principled way until a sufficient α-majority is reached ($\alpha >0.5$), distributing the entropy of the underlying taxonomic distribution as little as possible