BLASTcirc is a tool for finding whether or not a query sequence is a circular RNA (circRNA) by searching against a genome or transcriptome. BLASTcirc can determine whether query sequences contain back-splicing sites based on basic local alignment, provides the statistical significance of the potential circRNAs using a global alignment algorithm, and optimizes a composite score (score A) for each alignment by taking into account all potential genomic locations of back-splicing sites.

The current version of BLASTcirc provides circRNA search for ten plants (Arabidopsis, rice, maize, soybean, cotton, oilseed rape, tomato, cucumber, Chinese cabbage and grape). Read more about BLASTcirc at here.

local Blastcirc



BLASTcirc v1.0 online!
BLASTcirc beta version released!

Enter Query Sequence

Enter raw sequence or FASTA sequence(s)

Or, upload file


Word size

Mismatch penalty

Gap costs

Max number of results


Output type


Mismatch in junction sites

Splicing signal & exon-intron boundary

Max distance between start and end (bp)

How to cite this tool:

Xingchen Zhang, Qinjie Chu, Chu-Yu Ye, Xintian Zhu, Qian-Hao Zhu, Longjiang Fan. 2017. BLASTcirc: a web server for searching circular RNAs. Unpublished