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).

OTU QC: Contaminants

Contamint species can be introduced into your samples at every stage in the experimental protocol from sample collection to sequencing (e.g., residue on the flow-cell).

Detecting contaminants is difficult / impossible except in control samples e.g., distilled water, or a mock community. Control samples can be used to detect contaminants introduced in the stages from library preparation to sequencing. Note that cross-talk can also cause unexpected sequences in a control sample.