This BLAST server allows users to dynamically compare their sequences of interest against our 16S sequences or the Ribosomal Sequence Database.

The query sequences can either be copy-pasted in the box provided below or a file containing the sequences can be uploaded. Additional blast parameters can be providing by modifying the default values in the additional parameters box.

Database E-value

Enter sequence below in fasta format


Upload the sequence file: (example file)

Parameters (select for further options)

Advanced Parameters.

Filter Query Sequence. Matrix.
Word size. Threshold for extending hits.
Perform Gapped Alignment. Query Genetic Code.
Effective length of Database. Number of best hits to keep.
Effective Length of search space. Nucleotide Query Strand to use.
Lowercase filtering. Drop off value for ungapped extension.
Drop off value for gapped alignment. Drop off value for final gapped alignment.
Activate MegaBlast Algorithm. Frame shift penalty.