Video talks on 16S data analysis posted.

URMAP ultra-fast read mapper posted (paper).

~20% of taxonomy annotations in SILVA and Greengenes are wrong (paper).

Taxonomy prediction is <50% accurate for 16S V4 sequences (paper).

97% OTU threshold is wrong for species, should be 99% for full-length 16S, 100% V4 (paper).

Sequence database trimming

Where possible, sequences in database files should be trimmed to minimize terminal gaps. This reduces the memory required to store the database, improves the correlation between word count and sequence similarity for the USEARCH algorithm, and increases search speed by reducing the number of spurious word matches that must be counted or extended.