CALCULATE WITH CONFIDENCE

Bioinformatics & Sequence Analysis

Protein Reverse-Translation Degeneracy Workbench

Map every standard amino-acid residue to all synonymous NCBI table-1 codons, retain the exact combinatorial degeneracy and show a deterministic non-optimized representative record.

Biology · experimental measurements

Expose that a protein sequence usually corresponds to many possible coding records rather than presenting one arbitrary back-translation as the original DNA.

Private calculations in your browser · explicit inputs and model boundaries
Example preview · Short peptideSynonymous choices at every residue
1 · M1 codons
2 · K2 codons
3 · W1 codons

Each bar is the exact table-1 synonymous-codon count for one residue. The product of all bars' values gives the displayed coding-record degeneracy.

  1. 1EnterProvide the known values
  2. 2CalculateResults update automatically
  3. 3VerifyReview the details and units
Try an example

Use the 20 standard one-letter amino-acid codes; stop, gap and ambiguity symbols are excluded.

Calculation result

—

Enter valid values to see the result.

Your entries are calculated in this browser and are not submitted to 365CALCS.COM.

Feedback

Understand the relationship

The reasoning behind the result

Reverse translation is one-to-many

Nrecords = ∏ᵢ degeneracy(amino acid i)

The standard code maps several codons to many amino acids. Multiplying each residue's synonymous choices gives the exact number of compatible coding records under table 1.

Methionine and tryptophan have one standard codon; leucine, serine and arginine each have six.

A representative record needs a policy

The displayed representative chooses the alphabetically first standard codon for each residue so it is deterministic and auditable.

It is not the most frequent codon in any organism and is not claimed to be the original coding sequence.

GC bounds are attainable sequence bounds

For each residue, the least and most GC-rich synonymous codons contribute to independent lower and upper totals. These are exact combinatorial bounds under the selected code.

They do not predict expression, synthesis success or secondary structure.

Codon optimization is a different task

Organism codon tables, tRNA pools, context effects, motifs, repeats and manufacturing constraints would require explicit maintained evidence and an optimization objective.

None is inferred from the protein sequence alone.

Follow the numbers

Reverse-translate MKW

  1. M maps only to ATG under NCBI standard code table 1.
  2. K maps to AAA or AAG.
  3. W maps only to TGG.
  4. The exact combination count is 1 × 2 × 1 = 2.
  5. The deterministic alphabetic representative is ATGAAATGG, but both compatible records remain visible in the ledger.

The result enumerates standard-code possibilities; it does not recover a source organism or original gene.

Quick guide

How to use this calculator

  1. Confirm that the protein uses NCBI standard code table 1 and contains no stop or ambiguity symbols.
  2. Choose whether synonymous codons should be written as DNA or mRNA.
  3. Use the complete residue ledger and exact degeneracy count; do not treat the representative record as a biological reconstruction.

Calculation method

Calculation and interpretation

Expose that a protein sequence usually corresponds to many possible coding records rather than presenting one arbitrary back-translation as the original DNA.

Exact possible coding records = product of the standard-code synonymous-codon count for every residue. Minimum and maximum GC counts sum each residue's attainable codon bounds.

Worked example

Reverse-translate MKW

The result enumerates standard-code possibilities; it does not recover a source organism or original gene.

Exact possible coding records = product of the standard-code synonymous-codon count for every residue. Minimum and maximum GC counts sum each residue's attainable codon bounds.

Supported inputs

Precision and limits

NCBI standard code table 1

Alternative genetic codes and recoding events are outside this workflow.

Twenty standard residues

Stops, gaps, selenocysteine, pyrrolysine and ambiguous residue symbols are not reverse-translated.

No codon preference

The representative record uses a deterministic alphabetic rule, not an organism codon-usage table.

No design claim

Expression, synthesis, restriction sites, repeats, GC windows, mRNA structure and primer suitability are not optimized.

Computational support

Up to 500 residues are retained with an exact arbitrary-precision combination count and one row per residue.

Continue calculating

Related calculators