DNA Sequence Analysis Toolkit
Free suite for DNA/RNA sequence analysis: reverse complement, GC content, and protein translation with standard NCBI genetic code #1.
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Frequently Asked Questions
How is the inverse complement of a DNA sequence calculated?
The reverse complement is obtained in two steps: first, each base is replaced with its complement (A↔T, G↔C), then the sequence is inverted. For ATGC, the complement is TACG and the reverse complement is GCAT, corresponding to the template strand read from 5'→3'.
How is the GC content of a nucleotide sequence calculated?
GC% is the percentage of guanine (G) and cytosine (C) on total ACGT bases. Calculated as (G+C)/(A+T+G+C) × 100. An elevated GC% (>60%) indicates higher thermal stability of duplexes, relevant for primer design and evolutionary analysis.
What genetic code is used for translation?
The tool uses the NCBI Standard Genetic Code #1 (universal table for eukaryotic organisms and most prokaryotes). Translation starts from the first codon, stops at the first stop codon (TAA, TAG, TGA), and unknown codons are marked with 'X'.
Can I insert RNA sequences into the analyzer?
Yes. For RevComp and Translation the input can contain U (uracile); translation function automatically converts U→T before processing codons. Only bases A, C, G, T are counted for GC%; U is excluded from the denominator.
What is the maximum sequence length supported?
The instrument accepts sequences up to 1 million bases (1 Mb). For longer sequences, a dedicated bioinformatics tool is recommended (e.g. Biopython, EMBOSS). All processing occurs in the browser, so very long sequences can slow down calculations.
Are IUPAC codes supported for ambiguous bases?
Yes, in the inverse complement. IUPAC bases (R, Y, S, W, K, M, B, V, D, H, N) are correctly complemented: R (purine)↔Y (pyrimidine), K↔M, B↔V, D↔H. Unrecognized bases are mapped to 'N'. Only A, C, G, T/U are processed in GC% calculation and translation.
How is it used?
- Choose a function
Select the desired sheet: Reverse Complement, GC Content or Protein Translation.
- Insert sequence
Paste or type your DNA sequence (or RNA for RevComp/Translation). Accepted bases are A, T, G, C, U and standard IUPAC codes.
- Start Analysis
Click the calculation button to get the result. All calculations are performed in the browser, no data is sent to the server.
What is the DNA Sequence Toolkit and how does it work?
The DNA Sequence Toolkit is a browser-based suite for rapid analysis of nucleotide DNA and RNA sequences. It includes three essential basic bioinformatics functions: inverse complement calculation, GC content counting, and translation into amino acid sequence according to the standard NCBI genetic code #1.
The reverse complement is crucial in sequencing, primer PCR design, and oligonucleotide analysis. Given a 5' to 3' sequence, its reverse complement corresponds to the antiparallel strand read in the same direction, which actually participates in polymerization reactions.
GC% measures the proportion of guanine and cytosine bases to total ACGT. A high value implies greater thermal stability of duplexes (three hydrogen bonds G≡C vs two A=T), a critical parameter for optimizing primer and probe Tm, hybridization temperature, and challenging amplification robustness.
Translation of CDS to protein using the NCBI #1 codon table for eukaryotes, bacteria, and archaea. The tool processes input in triple nucleotide bases, stops at the first stop codon (TAA, TAG, TGA) and returns the amino acid sequence in single-letter IUPAC format.
All calculations occur entirely within the browser (pure JavaScript), without transferring sequences to external servers. Sequences up to 1 Mb are supported. For RNA: uracil (U) is accepted in both RevComp and Translation; only A, C, G, T bases are counted in GC%.
Practical example
- Input sequence:
ATGCGCATGC - Complement: complement every base (A→T, T→A, G→C, C→G) then invert →
GCATGCGCAT - GC content: G=3, C=3 out of 10 bases ACGT → (3+3)/10 × 100 = 60.0%
- Translation (reading from position 0): ATG=M, CGC=R, ATG=M -> protein
MRM(incomplete CDS - no stop codon in the next 10 nt)
Vocabulary Dictionary
- Revision Compensation
- Reverse Complement: sequence read in reverse direction (3'→5' becomes 5'→3'). Corresponds to the anti-parallel strand of double-stranded DNA.
- GC Content (%)
- Base Guanine (G) and Cytosine (C) Percentage in a Nucleotide Sequence. Influences thermal stability and behavior in PCR, cloning, and sequencing.
- Gene sequence
- Triplet of nucleotides that codes for an amino acid or a stop signal in protein translation. The standard genetic code defines 64 codons, of which 61 are sense and 3 are stop (TAA, TAG, TGA).
- Compact Data Sheet
- Coding Sequence: portion of messenger RNA (or corresponding DNA) translated into protein from start codon (ATG) to stop codon.
- A-DNA: A = Adenine B-DNA: B = Guanine C-RNA: C = Cytosine D-ss
- Codes per single letter for ambiguous bases: R(A/G), Y(C/T), S(G/C), W(A/T), K(G/T), M(A/C), B(C/G/T), V(A/C/G), D(A/G/T), H(A/C/T), N(any). Use in FASTA files with consensus sequences.
- Melting Point Temperature
- Temperature at which 50% of the double-stranded DNA is denatured. It's a function of GC% and primer/oligonucleotide length. Sequences with GC% > 60% require higher annealing temperatures in PCR.
Do you need a custom analysis?
This tool is free and informative. For in-depth analysis with AI on-prem - private data, zero cloud - contact Federico.