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11-Aug-2018 New paper describes octave plots for visualizing alpha diversity.

12-Jun-2018 New paper shows that one in five taxonomy annotations in SILVA and Greengenes are wrong.

18-Apr-2018 New paper shows that taxonomy prediction accuracy is <50% for V4 sequences.

05-Oct-2017 PeerJ paper shows low accuracy of closed- and open-ref. QIIME OTUs.

22-Sep-2017 New paper shows 97% threshold is wrong, OTUs should be 99% full-length 16S, 100% for V4.

UPARSE tutorial video posted on YouTube. Make OTUs from MiSeq reads.



OTU identifiers in sequence labels

OTU sequences must have OTU identifiers
An OTU table is generated by the otutab command or closed_ref command.. OTU identifiers are extracted from the sequence labels in the search database which contains OTU or ZOTU sequences.

OTU identifier syntax
First, usearch looks for an annotation otu=xxx; in the label. If this is found, then xxx is the OTU identifier. Otherwise, the OTU identifier is the sequence label with all annotations removed, i.e. all characters up to the first semi-colon (;) or the end of the label, which ever comes first.
The following labels all contain an OTU identifier with 123.