What is FASTA and how is it used?

FASTA is among the most popular formats for storing biological sequence data. Here is what it is and how it is used.

What is FASTA?

The FASTA format is a text-based file format for storing protein and nucleic acid sequences. FASTA files commonly have the .fasta or .fa file extensions.

A FASTA file can contain one or more sequences. A sequence "block" in FASTA starts with a single-line description. The description line always begins with a greater-than character (>).

The sequence description line is immediately followed by the lines of sequence data. The residues in the sequence are represented using single-letter codes.

Here is an example of one protein sequence in the FASTA format:


Bottom line

Whether you perform sequence analysis on a daily basis or only occasionally run BLAST, it is important that you are familiar with the FASTA format and can easily open FASTA file and navigate their contents. To open and view FASTA files, you can use the web-based Sequence Alignment Viewer which is free to use and does not require downloading or installation.

Related projects

Convert FASTQ files to FASTA format.
FASTQ, FASTA, bioinformatics
Open FASTA files in the browser.
bioinformatics, FASTA
Create sequence logo diagrams online.
bioinformatics, sequence analysis
Explore the human genome.
bioinformatics, genomics
A WASM port of the BLAST sequence alignment tool.
BLAST, WASM, bioinformatics
A WASM port of the MUSCLE sequence alignment tool.
MUSCLE, WASM, bioinformatics
A WASM port of MrBayes.
MrBayes, WASM, bioinformatics
Running DESeq2 in the browser with WebAssembly.
A tool to generate plasmid maps from GenBank files.
bioinformatics, svg

Made by Anton Vasetenkov.

If you want to say hi, you can reach me on LinkedIn or via email. If you like my work, you can support me by buying me a coffee.