DNA Translation Tool
Translate a DNA sequence into a protein across all 6 reading frames.
Ambiguous bases such as N are translated as X and keep their position, so the reading frame downstream is unaffected.
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What it does
The DNA Translation tool translates a nucleotide sequence into protein in all six reading frames at once: three on the forward strand and three on the reverse complement. Paste a DNA sequence and each frame is reported as a single-letter amino acid string with its residue count, its stop codon count, start and stop codons highlighted, and a copy button per frame. It is the quickest way to see what an open reading frame could encode, to confirm that a cloned insert translates as expected, and to show how much a single missing base changes. The sequence is processed entirely in your browser and nothing is uploaded.
How it works
Translation reads the sequence in non-overlapping triplets called codons, each of which maps to one amino acid through the standard genetic code. This tool uses the standard nuclear table in its DNA form, so thymine rather than uracil, and marks the three stop codons TAA, TAG and TGA with an asterisk while the other 61 codons become their single-letter residue codes. Because the correct frame is not known in advance, all six are computed: three starting at the first, second and third position of the forward strand, and three on the reverse complement, which is produced by reversing the sequence and swapping A with T and C with G. Methionines that come from an ATG codon are highlighted in green so a candidate reading frame is easy to spot, but no frame is selected for you and ATG is translated as methionine wherever it appears. Ambiguous positions such as N, R or Y are legitimate sequence characters and are kept in place, each translated as X, so they mark the uncertainty without disturbing the reading frame downstream. A trailing group of one or two nucleotides that cannot complete a codon is discarded rather than padded with unknowns.
Worked example
Take the nine base sequence ATGGCCTGA. Frame plus one reads ATG GCC TGA and gives MA*: methionine, alanine, stop, so two residues and one stop. Frame plus two shifts a single base and reads TGG CCT, leaving the final A as an incomplete codon, which gives WP with two residues and no stop. Frame plus three reads GGC CTG and leaves GA unread, giving GL. The reverse complement of ATGGCCTGA is TCAGGCCAT, and its three frames give SGH, QA and RP respectively. That is six different answers from one short sequence, which is exactly why all six frames are shown rather than the first one being trusted. A longer read behaves the same way and the consequences compound: a single deleted base shifts every downstream codon, so a sequence that should read methionine, alanine, alanine will produce a completely unrelated peptide from the point of the error onwards. Watch the residue and stop counts under each frame, because the frame carrying a real coding sequence usually shows a long run of residues with a single stop codon at the end.
When to use it
Use it to see what a cloned insert or a PCR product could encode, to check that a reading frame survived an editing step, and to demonstrate to students how a frameshift changes a protein. Three details decide whether the answer is right. The first is that ambiguous bases are preserved rather than removed. N, R, Y and the other IUPAC codes are legitimate sequence characters, and each occupies its position and translates to X, so ATGNCCTGA reads as methionine, unknown, stop rather than silently closing the gap. Deleting such a character instead would shift every downstream codon, which is the classic reason a translation comes back full of stops; only genuinely foreign characters such as digits or punctuation are stripped, and the tool says so when that happens. The second is that uracil is accepted: an RNA sequence pasted as AUGGCCUGA is read as DNA by converting U to T, since the two are equivalent in the standard codon table. The third is the reverse strand, because a gene can sit on either strand, so all six frames should be scanned and the longest open reading frame starting with ATG identified. The standard nuclear code is used throughout, so a mitochondrial sequence, where TGA codes for tryptophan and ATA for methionine, will be mistranslated.
FAQ
- What are the six reading frames?
- Three on each strand. Because a codon is three bases, the first, second and third base of the sequence each start a different frame, and the same is true of the reverse complement. A nine base sequence such as ATGGCCTGA therefore has six possible translations: MA*, WP and GL on the forward strand, and SGH, QA and RP on the reverse. Only one of them is the real protein, which is why all six are shown.
- Why is my translation full of stops or obviously out of frame?
- Usually because characters that were not nucleotides were removed before translating, or because the wrong frame is being read. Ambiguous bases are safe: N, R, Y and the other IUPAC codes keep their position and show up as X, so ATGNCCTGA reads as methionine, unknown, stop. Digits and punctuation are not safe, and are stripped with a warning, because dropping even one base shifts every downstream codon. Check the residue and stop counts under each frame: the one carrying real coding sequence usually shows a long run of residues ending in a single stop.
- Does the tool find open reading frames for me?
- No. All six frames are translated in full and none is preferred. ATG is translated as methionine wherever it appears rather than being treated as a start signal, and a trailing one or two bases that cannot form a codon are discarded. To find the coding region, look for the frame with a long run of residues and a single stop codon at the end, then confirm it against the annotation or the cloning strategy.
- Why does the result differ from my sequencing report?
- Three things to check. First, strand and frame: a report may show only the reverse complement, or only the frame that was annotated. Second, the genetic code table: this tool uses the standard nuclear code, so a mitochondrial sequence, where TGA is tryptophan and ATA is methionine, comes out wrong. Third, whether the input was DNA or RNA: uracil is accepted and converted to thymine, so an RNA sequence can be pasted directly, but a file carrying digits, whitespace or line breaks will have those characters stripped before translation, and ambiguous codes such as N will appear as X.