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Non-Standard Genetic Code Tables: Mitochondrial, Bacterial, and Ciliate Codon Differences (NCBI transl_table Reference)

All 27 NCBI genetic code tables with per-codon differences from the standard table, searchable by table number or codon.

All 27 genetic code tables defined by NCBI, with per-codon differences from the standard table. The query box below lets you select a table number and enter a codon to see what amino acid it encodes in that table.

All 27 NCBI genetic code tables

ID Name Diffs vs standard Stop codons Start codons
1 The Standard Code (transl_table=1) — TAA TAG TGA ATG CTG TTG
2 The Vertebrate Mitochondrial Code (transl_table=2) 4 AGA AGG TAA TAG ATA ATC ATG ATT GTG
3 The Yeast Mitochondrial Code (transl_table=3) 6 TAA TAG ATA ATG GTG
4 The Mold, Protozoan, and Coelenterate Mitochondrial Code and the Mycoplasma/Spiroplasma Code (transl_table=4) 1 TAA TAG ATA ATC ATG ATT CTG GTG TTA TTG
5 The Invertebrate Mitochondrial Code (transl_table=5) 4 TAA TAG ATA ATC ATG ATT GTG TTG
6 The Ciliate, Dasycladacean and Hexamita Nuclear Code (transl_table=6) 2 TGA ATG
9 The Echinoderm and Flatworm Mitochondrial Code (transl_table=9) 4 TAA TAG ATG GTG
10 The Euplotid Nuclear Code (transl_table=10) 1 TAA TAG ATG
11 The Bacterial, Archaeal and Plant Plastid Code (transl_table=11) 0 TAA TAG TGA ATA ATC ATG ATT CTG GTG TTG
12 The Alternative Yeast Nuclear Code (transl_table=12) 1 TAA TAG TGA ATG CTG
13 The Ascidian Mitochondrial Code (transl_table=13) 4 TAA TAG ATA ATG GTG TTG
14 The Alternative Flatworm Mitochondrial Code (transl_table=14) 5 TAG ATG
15 Blepharisma Nuclear Code (transl_table=15) 1 TAA TGA ATG
16 Chlorophycean Mitochondrial Code (transl_table=16) 1 TAA TGA ATG
21 Trematode Mitochondrial Code (transl_table=21) 5 TAA TAG ATG GTG
22 Scenedesmus obliquus Mitochondrial Code (transl_table=22) 2 TAA TCA TGA ATG
23 Thraustochytrium Mitochondrial Code (transl_table=23) 1 TAA TAG TGA TTA ATG ATT GTG
24 Rhabdopleuridae Mitochondrial Code (transl_table=24) 3 TAA TAG ATG CTG GTG TTG
25 Candidate Division SR1 and Gracilibacteria Code (transl_table=25) 1 TAA TAG ATG GTG TTG
26 Pachysolen tannophilus Nuclear Code (transl_table=26) 1 TAA TAG TGA ATG CTG
27 Karyorelict Nuclear Code (transl_table=27) 3 ATG
28 Condylostoma Nuclear Code (transl_table=28) 3 ATG
29 Mesodinium Nuclear Code (transl_table=29) 2 TGA ATG
30 Peritrich Nuclear Code (transl_table=30) 2 TGA ATG
31 Blastocrithidia Nuclear Code (transl_table=31) 3 ATG
32 Balanophoraceae Plastid Code (transl_table=32) 1 TAA TGA ATA ATC ATG ATT CTG GTG TTG
33 Cephalodiscidae Mitochondrial UAA-Tyr Code (transl_table=33) 4 TAG ATG CTG GTG TTG

Codon-level differences from the standard code

ID Codon Standard This code
2 AGA R Stop
2 AGG R Stop
2 ATA I M
2 TGA Stop W
3 ATA I M
3 CTA L T
3 CTC L T
3 CTG L T
3 CTT L T
3 TGA Stop W
4 TGA Stop W
5 AGA R S
5 AGG R S
5 ATA I M
5 TGA Stop W
6 TAA Stop Q
6 TAG Stop Q
9 AAA K N
9 AGA R S
9 AGG R S
9 TGA Stop W
10 TGA Stop C
11 — — identical to standard
12 CTG L S
13 AGA R G
13 AGG R G
13 ATA I M
13 TGA Stop W
14 AAA K N
14 AGA R S
14 AGG R S
14 TAA Stop Y
14 TGA Stop W
15 TAG Stop Q
16 TAG Stop L
21 AAA K N
21 AGA R S
21 AGG R S
21 ATA I M
21 TGA Stop W
22 TAG Stop L
22 TCA S Stop
23 TTA L Stop
24 AGA R S
24 AGG R K
24 TGA Stop W
25 TGA Stop G
26 CTG L A
27 TAA Stop Q
27 TAG Stop Q
27 TGA Stop W
28 TAA Stop Q
28 TAG Stop Q
28 TGA Stop W
29 TAA Stop Y
29 TAG Stop Y
30 TAA Stop E
30 TAG Stop E
31 TAA Stop E
31 TAG Stop E
31 TGA Stop W
32 TAG Stop W
33 AGA R S
33 AGG R K
33 TAA Stop Y
33 TGA Stop W

Why you need this reference

Translating mitochondrial sequences with the standard genetic code gives wrong proteins. Take the vertebrate mitochondrial code (table 2) as an example: it differs from the standard table in four positions — TGA changes from stop to tryptophan, ATA changes from isoleucine to methionine, and AGA and AGG change from arginine to stop. Using the standard table, a protein is erroneously truncated at the first TGA, while the actual stop signals go unrecognized.

GenBank records use /transl_table=N to indicate which table applies; N is the table number shown here. When working with sequences from non-nuclear genomes, non-model organisms, or environmental samples, confirm the table number before translating.

Table 11 (bacterial, archaeal, and plant plastid) is identical to the standard table — zero differences — but it is listed separately so that annotation pipelines can explicitly declare they are using the bacterial code rather than implicitly matching the standard table by coincidence.

Data source

All data are taken from the NCBI page The Genetic Codes (compiled by Elzanowski A and Ostell J, https://www.ncbi.nlm.nih.gov/Taxonomy/Utils/wprintgc.cgi, last updated 2024-09-23). The page was fetched with curl and parsed programmatically — no manual transcription, no model paraphrase. Each table was verified to cover exactly 64 non-redundant codons; the difference columns were computed by position-by-position comparison against table 1.

FAQ

How do I know which table to use?

The /transl_table=N qualifier on CDS features in GenBank records gives you the table number. For your own data, choose based on the source material: nuclear genomes generally use table 1, bacteria use table 11, vertebrate mitochondria use table 2, invertebrate mitochondria use table 5. For non-model organisms and environmental samples, look up the actual table used for that taxon — do not assume the standard table.

Table 11 and table 1 are identical — why list them separately?

The difference is indeed zero. The separate entry exists so that annotation pipelines can explicitly state that the bacterial code is in use, rather than silently matching the standard table. The semantics differ even when the values are the same.

What are the consequences of using the wrong table?

The canonical example is translating vertebrate mitochondrial sequences with the standard table: TGA is a stop codon in the standard table but encodes tryptophan in table 2, so the protein is erroneously truncated at the first TGA; at the same time, AGA and AGG are stop codons in table 2 but are read as arginine under the standard table, so the actual stop signals are missed.

Do these tables change?

Tables are added over time. The most recent NCBI update was 2024-09-23; several tables beyond number 24 were added in recent years. The data on this page are parsed programmatically from the NCBI source page and can be refreshed by re-fetching.

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