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).

UDB database files

A UDB file is a database file that contains sequences and a k-mer index for those sequences. A UDB file is created using makeudb_usearch, makeudb_ublast or makeudb_sintax.

The udb2fasta command can be used to convert the UDB file to FASTA.

See indexing options for a description of index parameters.