DNA reverse & reverse complement
DNA is usually written 5′ → 3′ on one strand. The reverse of a sequence is the same strand read backwards (3′ → 5′ order). The reverse complement is the sequence of the opposite strand, also written 5′ → 3′, with each base swapped for its Watson–Crick partner (A↔T, G↔C).
These transforms are routine in molecular biology: checking primer orientation, copying a feature annotated on the minus strand, or preparing an insert sequence for cloning. If a gene is on the antisense chromosome strand, you often need the reverse complement before you order oligos or compare to a reference file given on the plus strand.
Reverse alone flips direction without base pairing. Reverse complement is what you need when you want the sequence of the partner strand — for example, the sequence a forward primer would match on the opposite duplex strand.
How to use this tool
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Paste DNA (A, C, G, T; U is read as T) or load a FASTA file. Header lines starting with
>are skipped; sequence lines from the first record are concatenated. - Choose DNA reverse or DNA reverse complement from the operation menu.
- Click Transform. The result appears in the output box — use Copy result to paste elsewhere.
- Use Reset to clear the form and start again. Characters other than A, C, G, T, N, and U are ignored (you will see a warning if any were dropped).
Common workflows
After obtaining the reverse complement of a coding region on the minus strand, open DNA translation to read all three forward frames and locate open reading frames or check that a construct stays in frame.
To compare your transformed sequence with a reference or mutant, use the sequence aligner (pairwise DNA or protein). When designing primers that include restriction sites or Tm targets, see the primer design guide — then verify internal cut sites with the restriction digest analyser.
Related resources on The Bond Lab
- DNA translation — three forward reading frames after orientation is fixed.
- Sequence aligner — pairwise or multi-sequence DNA/protein alignment.
- Primer design guide — qPCR and cloning primer workflow with NCBI Primer-BLAST.
- Restriction digest analyser — map enzyme sites on the sequence you plan to clone.
Data & privacy
Sequences are transformed entirely in your browser; they are not uploaded to a server for this tool. Do not paste patient-identifiable or confidential unpublished data unless your policy allows. See the privacy policy for site-wide analytics and advertising.