cblaster is a tool for finding clusters of co-located homologous sequences
in BLAST searches.
Given a collection of protein sequences, cblaster can search sequence databases
remotely (via NCBI BLAST API) or locally (via DIAMOND). Search results are parsed
and filtered based on user thresholds for identity, coverage and e-value. The genomic
coordinates of remaining hits are obtained from the NCBI's Identical Protein
Group (IPG) database (or a local database in local searches). Finally,
cblaster scans for instances of collocation and generates visualisations:
cblaster can be installed via pip:
$ pip3 install cblaster --useror by cloning the repository and installing:
$ git clone https://github.com/gamcil/cblaster.git
...
$ cd cblaster/
$ pip3 install .cblaster is tested on Python 3.6, and its only external Python dependency is
the requests module (used for interaction with NCBI APIs).
If you want to perform local searches, you should have diamond installed and available
on your system $PATH.
cblaster will throw an error if a local search is started but it cannot find
diamond or diamond-aligner (alias when installed via apt) on the system.
cblaster accepts FASTA files and collections of valid NCBI sequence identifiers
(GIs, accession numbers) as input.
A remote search can be performed as simply as:
$ cblaster search --query_file query.fastaFor example, to remotely search the burnettramic acids gene cluster, bua , against the NCBI's nr database:
$ cblaster search -qf bua.fasta
[12:14:17] INFO - Starting cblaster in remote mode
[12:14:17] INFO - Launching new search
[12:14:19] INFO - Request Identifier (RID): WHS0UGYJ015
[12:14:19] INFO - Request Time Of Execution (RTOE): 25s
[12:14:44] INFO - Polling NCBI for completion status
[12:14:44] INFO - Checking search status...
[12:15:44] INFO - Checking search status...
[12:16:44] INFO - Checking search status...
[12:16:46] INFO - Search has completed successfully!
[12:16:46] INFO - Retrieving results for search WHS0UGYJ015
[12:16:51] INFO - Parsing results...
[12:16:51] INFO - Found 3944 hits meeting score thresholds
[12:16:51] INFO - Fetching genomic context of hits
[12:17:14] INFO - Searching for clustered hits across 705 organisms
[12:17:14] INFO - Writing summary to <stdout>
Aspergillus mulundensis DSM 5745
================================
NW_020797889.1
--------------
Query Subject Identity Coverage E-value Bitscore Start End Strand
QBE85641.1 XP_026607259.1 75.56 99.5918 0 742 1717881 1719409 -
QBE85642.1 XP_026607260.1 89.916 100 0 667 1719650 1720797
QBE85643.1 XP_026607261.1 89.532 83.1169 0 832 1721494 1722934
QBE85644.1 XP_026607262.1 64.829 98.9218 6.51e-157 455 1723252 1724467 -
QBE85645.1 XP_026607263.1 69.97 100 6.93e-157 449 1725113 1726277 -
QBE85646.1 XP_026607264.1 82.759 96.8447 0 670 1726892 1728302
QBE85647.1 XP_026607265.1 72.674 99.2048 0 764 1729735 1731338
QBE85648.1 XP_026607266.1 56.098 98.324 4.24e-64 205 1731701 1732402 -
QBE85649.1 XP_026607267.1 79.623 99.8746 0 6573 1732820 1745289
...A query sequence absence/presence matrix can be generated using the --binary argument:
Organism Scaffold Start End QBE85641.1 QBE85642.1 QBE85643.1 QBE85644.1 QBE85645.1 QBE85646.1 QBE85647.1 QBE85648.1 QBE85649.1
Aspergillus mulundensis DSM 5745 NW_020797889.1 1717881 1745289 1 1 1 1 1 1 1 1 1
Aspergillus versicolor CBS 583.65 KV878126.1 3162095 3187090 1 1 1 0 1 1 1 1 1
Pseudomassariella vexata CBS 129021 MCFJ01000004.1 1606356 1628483 1 1 1 0 0 1 0 1 1
Hypoxylon sp. CO27-5 KZ112517.1 92119 112957 1 1 1 0 0 0 1 0 1
Hypoxylon sp. EC38 KZ111255.1 514739 535366 1 1 1 0 0 0 1 0 1
Epicoccum nigrum ICMP 19927 KZ107839.1 2116719 2142558 1 1 0 0 0 1 1 0 1
Aureobasidium subglaciale EXF-2481 NW_013566983.1 700476 718693 1 1 0 0 0 1 1 0 0
Aureobasidium pullulans EXF-6514 QZBF01000009.1 18721 34295 1 1 0 0 0 1 1 0 0
Aureobasidium pullulans EXF-5628 QZBI01000512.1 329 13401 1 0 0 0 0 1 1 0 0
cblaster can also generate fully interactive visualisations of the binary
table. To view an example, click here.
For further usage examples and API documentation, please refer to the documentation.
If you found this tool useful, please cite:
Gilchrist, C.L.M., Booth, T.J., Chooi, Y.-H., 2020. cblaster: a remote search tool for rapid identification and visualisation of homologous gene clusters. bioRxiv 2020.11.08.370601. https://doi.org/10.1101/2020.11.08.370601
cblaster makes use of the following tools:
Buchfink, B., Xie, C. & Huson, D. H. Fast and sensitive protein alignment using DIAMOND. Nat. Methods 12, 59–60 (2015).
Acland, A. et al. Database resources of the National Center for Biotechnology Information. Nucleic Acids Res. 42, 7–17 (2014).