Codon Plot

Generate an ASCII codon plot using codon frequency data to highlight usage bias across a sequence.

Tool Configuration

Configure the parameters for Codon Plot

DNA Sequence*

Paste raw DNA or FASTA-formatted sequence (limit 50,000,000 bases). Only IUPAC DNA characters are retained.

Codon Usage Table (GCG format)*

AmAcid  Codon      Number    /1000     Fraction   ..
 
Gly     GGG     50527.00     11.12      0.15
Gly     GGA     39036.00      8.59      0.12
Gly     GGT    114185.00     25.14      0.34
Gly     GGC    130043.00     28.63      0.39
 
Glu     GAG     83804.00     18.45      0.32
Glu     GAA    179460.00     39.51      0.68
Asp     GAT    146794.00     32.32      0.63
Asp     GAC     87759.00     19.32      0.37
 
Val     GTG    115687.00     25.47      0.36
Val     GTA     51020.00     11.23      0.16
Val     GTT     86572.00     19.06      0.27
Val     GTC     67356.00     14.83      0.21
 
Ala     GCG    146264.00     32.20      0.34
Ala     GCA     93390.00     20.56      0.22
Ala     GCT     73677.00     16.22      0.17
Ala     GCC    113412.00     24.97      0.27
 
Arg     AGG      7423.00      1.63      0.03
Arg     AGA     12345.00      2.72      0.05
Ser     AGT     41544.00      9.15      0.15
Ser     AGC     70867.00     15.60      0.26
 
Lys     AAG     51685.00     11.38      0.25
Lys     AAA    156169.00     34.38      0.75
Asn     AAT     84846.00     18.68      0.46
Asn     AAC     98018.00     21.58      0.54
 
Met     ATG    123604.00     27.21      1.00
Ile     ATA     24233.00      5.34      0.09
Ile     ATT    135873.00     29.92      0.50
Ile     ATC    111878.00     24.63      0.41
 
Thr     ACG     63696.00     14.02      0.26
Thr     ACA     35995.00      7.93      0.15
Thr     ACT     43256.00      9.52      0.18
Thr     ACC    103121.00     22.70      0.42
 
Trp     TGG     65630.00     14.45      1.00
End     TGA      4428.00      0.97      0.30
Cys     TGT     23461.00      5.17      0.45
Cys     TGC     28747.00      6.33      0.55
 
End     TAG      1172.00      0.26      0.08
End     TAA      9006.00      1.98      0.62
Tyr     TAT     75774.00     16.68      0.58
Tyr     TAC     55847.00     12.30      0.42
 
Leu     TTG     60322.00     13.28      0.13
Leu     TTA     62823.00     13.83      0.13
Phe     TTT    100128.00     22.05      0.57
Phe     TTC     74885.00     16.49      0.43
 
Ser     TCG     39546.00      8.71      0.15
Ser     TCA     35837.00      7.89      0.13
Ser     TCT     42367.00      9.33      0.16
Ser     TCC     40365.00      8.89      0.15
 
Arg     CGG     25751.00      5.67      0.10
Arg     CGA     16607.00      3.66      0.07
Arg     CGT     93997.00     20.70      0.37
Arg     CGC     96053.00     21.15      0.38
 
Gln     CAG    130898.00     28.82      0.66
Gln     CAA     67129.00     14.78      0.34
His     CAT     57585.00     12.68      0.57
His     CAC     43743.00      9.63      0.43
 
Leu     CTG    231373.00     50.94      0.49
Leu     CTA     18067.00      3.98      0.04
Leu     CTT     51442.00     11.33      0.11
Leu     CTC     48147.00     10.60      0.10
 
Pro     CCG    101467.00     22.34      0.51
Pro     CCA     38663.00      8.51      0.20
Pro     CCT     32678.00      7.19      0.17
Pro     CCC     24383.00      5.37      0.12

Provide a codon usage table in GCG format. Fractions are recalculated per amino acid to match legacy SMS behavior.

Enter DNA Sequence

Paste a DNA sequence (up to 50 million bases) in FASTA format or raw text. The tool accepts only valid IUPAC DNA characters (A, T, G, C, and ambiguities like N, R, Y). Non-DNA characters are automatically removed.

Provide Codon Usage Table

Enter a codon usage table in GCG format showing codon frequencies for your organism. The default table is for E. coli. You can obtain organism-specific tables from the Codon Usage Database. The tool recalculates fractions per amino acid to normalize usage.

Interpret the ASCII Plot

The output shows an ASCII bar chart for each codon in your sequence. Each line displays the codon position, the codon triplet, amino acid, and a bar whose length represents the relative frequency of that codon for its amino acid. Longer bars indicate more commonly used codons.

Applications

Use codon plots to visualize codon bias in genes, identify rare codons that may slow translation, optimize genes for heterologous expression, detect horizontal gene transfer, or compare native and synthetic gene sequences. Highly biased usage appears as consistently long bars for certain codons.

How to Interpret

Understanding the ASCII plot output

Per-Codon Rows

Each codon is printed with its position in the sequence and the corresponding amino acid assignment from the usage table.

Bar Length

The bar of X characters is proportional to the codon‘s fraction within its amino acid family (0 to 1.0). Longer bars indicate preferred codons.

Custom Tables

Paste alternative codon usage tables from species-specific databases to compare expression compatibility or visualize codon bias.

Sequence Design

Identify clusters of rare codons that may reduce translation efficiency when designing synthetic genes or optimizing heterologous expression.