Read a DNA sequence in your browser
Codon is a free tool for biology students and hobbyists who want to
inspect a stretch of DNA without installing SnapGene or signing into
Benchling. Paste a sequence and it works out the GC content, all six
reading frames, every open reading frame, the protein each frame
codes for, the codon counts, and any common restriction sites. It
all runs on your own machine and updates as you type.
What Codon shows you
-
GC content as a live percentage with a stacked bar
split by A, C, G and T, so base composition reads at a glance.
-
Six-frame translation: all three forward frames and
all three reverse-complement frames, translated to protein and
refreshed on every keystroke.
-
Open reading frames: every ATG-to-stop run across all
six frames, sorted longest first. The longest is boxed on the
sequence, and clicking any other one in the list jumps to it.
-
Codon usage: every codon in the sequence with its
count and share, sorted by frequency.
-
Restriction sites: matches for common Type II enzymes
(EcoRI, BamHI, HindIII, NotI, XhoI, PstI) marked inline and listed by
position.
How to use it
-
Paste a raw DNA sequence into the box, or press Load example
to try a real gene. Whitespace and line breaks from FASTA files are
ignored; anything that is not A, C, G or T is flagged.
-
Watch the GC content and reading frames update. The longest open
reading frame is highlighted directly on the sequence.
-
Click any ORF in the list to highlight it on the sequence and scroll
to it.
Questions
- Is my sequence uploaded anywhere?
-
No. Codon runs entirely in your browser. Nothing you paste leaves your
computer, and there is no account or server behind it.
- What is an open reading frame?
-
A stretch that starts at an ATG start codon and runs to the next
in-frame stop codon. Codon scans all six frames and lists every one it
finds, longest first.
- Which genetic code does it use?
-
The standard genetic code (NCBI translation table 1). Ambiguous or
incomplete codons translate to X.
- How long a sequence can I paste?
-
Up to 100,000 bases. Codon is built for genes, operons and plasmid
fragments rather than whole genomes, so longer pastes are turned away
with a message instead of freezing the tab.
- Does it cost anything?
-
No. Codon is free and open source under the MIT license.