← Bioinformatics Lab
Project 01 • Sequence Analysis
DNA Sequence Analyzer.
Inspect a DNA sequence directly in your browser. Measure nucleotide composition, GC and AT content, and generate complementary and reverse-complement strands.
Input
Enter a DNA sequence
Accepted bases: A, T, C and G. Spaces, line breaks and FASTA header lines beginning with “>” are ignored.
Paste a sequence or load the example to begin.
Sequence overview
Length
0
nucleotides
GC content
0%
G + C bases
AT content
0%
A + T bases
GC / AT ratio
0
composition ratio
Nucleotide composition
A
Adenine
0 0%
T
Thymine
0 0%
C
Cytosine
0 0%
G
Guanine
0 0%
Derived sequences
Normalized sequence
Uppercase DNA sequence after whitespace and FASTA header removal.
Complementary strand
Base pairing follows A↔T and C↔G.
Reverse complement
The complementary sequence read in reverse orientation.
Sequence preview
First and last bases for a quick visual check of longer inputs.
Interpretation
What do these measurements mean?
These are foundational descriptive calculations used when inspecting nucleotide sequences. They describe the sequence; they do not identify biological function on their own.
GC content
The percentage of nucleotides that are guanine or cytosine.
The percentage of nucleotides that are guanine or cytosine.
Complement
A strand generated by DNA base-pairing rules: A with T, and C with G.
A strand generated by DNA base-pairing rules: A with T, and C with G.
Reverse complement
The complement written in the opposite direction, commonly used when working with the opposite DNA strand.
The complement written in the opposite direction, commonly used when working with the opposite DNA strand.
Educational bioinformatics tool. Analysis is performed locally in the browser; this version does not upload or store the entered sequence.