Fig. 1

Simple representative trees representing the two different tree formats. Panel a shows a tree in which replicate tips, each with a count of 1, are added when the sequence is found multiple times. Panel b shows a tree representing the same data, but with replicate sequences represented by a single tip (e.g. as would occur if one picked OTUs and built the tree using a representative sequence for each OTU), and has a count related to each tip’s abundance in each different sample