The FASTA file format (.fasta or .fa) is used to specify the reference sequence for an imported genome. Each sequence in the FASTA file represents the sequence for a chromosome. The sequence name in the FASTA file is the chromosome name that appears in the chromosome drop-down list in the IGV tool bar. IGV orders the chromosomes based on their names, not their order in the FASTA file.

A FASTA file is a text file. Each sequence begins with a single-line description, followed by lines of sequence data. The single-line description contains a greater-than (>) symbol in the first column, followed by the sequence name. For a complete description of the FASTA file format, see

Note that FASTA files are only used for defining reference sequences, they cannot be "loaded" from the file menu.