Example of FASTA format

The FASTA format is a text-based format for representing either nucleotide sequences or amino acid (protein) sequences, in which nucleotides or amino acids are represented using single-letter codes. The format also allows for sequence names and comments to precede the sequences. The format has become a near-universal standard in the field of bioinformatics.

The first line in a FASTA file started either with a ">" (greater-than) symbol, holds a summary description of the sequence, often starting with a unique library accession number.

Following the initial line (used for a unique description of the sequence) is the actual sequence itself in a standard one-letter character string.