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).

fastx_split command

The fastx_split command divides a FASTA or FASTQ file into roughly equal-sized pieces. The size of a piece is measured by the file size in bytes rather than the number of sequences or number of sequence letters.

The -splits n option specifies the desired number of pieces. You may get n+1 pieces.

The -outname option specifies a pattern for the output file names, which are always FASTA. There must be a '@' character in the pattern, which is replaced by the split number 1, 2, 3...

Example

usearch -fastx_split db.fastq -splits 10 -outname split@.fa