Fig. 1

Schematic diagram of clade exclusion experiment. a is a diagram of the community composition structure in a simulated query dataset. All genomes in the simulated query dataset are from the two orders represented by the nodes colored with ‘green’ and ‘yellow’. b is a diagram of creating ‘Order_excluded’ reference database. All nodes in (b) stands for the original reference dataset A. Nodes colored with ‘green’ and ‘yellow’ are corresponding to the ones in (a) with same colors. The genomes under the nodes which are covered by the light blue part are excluded from reference dataset A to construct ‘Order_excluded’ database. In this figure, ‘+’ means that the inferior details are condensed, and ‘-’ means these details are expanded