Fig. 4

OTU clustering methods perform variably. a Eight methods were used on control communities of known composition to report OTU counts compared to known sample diversity (black dotted lines = number of genus; grey dotted line = number of species). Non-bacterial sequences were removed as part of sequence processing. Similar results were obtained when singletons were also removed (Additional file 5). b A group of 190 single isolates were independently sequenced in order to test varying OTU clustering algorithm’s ability to correctly identify 1 OTU within the input sample. c When these individual isolates were combined, the number of OTUs generated often lies between the known number of unique genera and species within the samples