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).

Creating a bit vector file for the search_16s command

See also
search_16s command

Bit vector files are created by the udb2bitvec command. The recommended sequence database is the Greengenes 97% representative set. You should use the -wordlength 13 option of makeudb_usearch to create the udb file, as shown below.

usearch -makeudb_usearch gg97.fa -wordlength 13 -output gg97.udb

usearch -udb2bitvec gg97.udb -output gg97.bitvec