A sequence in the FASTA format begins with a single-line description, followed by lines of sequence data. The description line is distinguished from the sequence data by a greater-than (">") symbol in the first column. The letters for DNA sequences can be either in upper case or in lower case. Any space, return, or tab in the file will be ignored. Any character not in the standard coding (A, T, C, and G), e.g., Z or 3, will be treated as an unknown base. Finally, an unknown base may be indicated by using X. An example:
>ORFA00005
ATGTATGAAGTTTTAGTGGTTGTTTACTTGTTGGTTGCATTAGGGGTCAATTTACA
GGTTTAATTGGCCTGATCTTAATCCAGCAGGGTAAAGGAGCTCTAGCCATTGCGTT
GACATGGGGGCCTCATTTGGCGCCGGTGCATCAGGTACCTTAACATTAGAACATTA
TTTGGTTCAAGCGGTTCAGGTAACTTCCTGACACGCACAACGCTAGCCATTGCGTT
GCAATCCTAGCCATTGCGTTTTTTACCTTAAGTTTGCTAATTGGGGTCAATTTACA
GCAATTTAAGTGCAAACCACGCAAAAAATGAAGATGCATGGACTAGCCATTGCGTT
AAATTTAGGTTCAGACACTGAACAGGTTACCCAACCTGTTGAACATTAGAACATTA
GGAACCGAAAAGTCAGAAACAAAAATTCCTGAC
>ORFA00006
TTGTTTTTTCGGGGGTCAATTTTGGCAACATTAGAATCCAGACTGAAGCATTAGGC
GGCAGACATGCTCAAAGTGCCTGTGGAAGCATTAGGCTTTCAACCAGCATTTGGCA
TTTGGGGTATTGAATATGTACAAGCCGGTAAACATTCCATACTGCAGCGACTAGCA
CGCGTGTTCATTGATGGTGAGAATGGCATCAATATCGAAGATTGGAAGCATTAGGC
GCCAACGTAAGTCGCCAAGTCAGTGCTGTGCTAGATGTTGAAGAGAAGCATTAGGC
CCCTATTTCTACTGAATATACCTTAGAGGTTTCTTCGCCTGGTGCAGCATTTGGCA
AGATAGACCGCTGTTCACTGCTGAACAATACGCGGCCTATGTCGCAGCGACTAGCA
CGAGGATGTCAAACTTCAACTGACTATGCCTGTCGCGGGCAGTCGAAGCATTAGGC
>ORFA00007
GTGGAACGGCCTTTTCATTTGAAACCGCTTCAGCGACTAGCAGAGCGTGTTCATTG
TCTCTTTATTCATTTTGTCTTGCCTCGTTCACCTTGAAACCATCGTTTCTTCGCCT
AACTTTGCGATGATGTTGCCTTTACGGATATTATCCAAGGCGACGCGTGTTCATTG
CCAGCTCTTTACCATTCACATTCACCGACAGCATTTGGCCGTCAGTTTCTTCGCCT
AACCTGAGTAATGGCGCCTTT
>ORF00007 acyl carrier protein (acpP)
ttgacggaagcgggcggctcgttgcaccccgttcagccttgcgcccccgcttct
cgtgtacactgcgggcacttcagtttcaggaggaatttggtaatggcgactttt
gtgaaagatgtgattgtggacaagctcggtgtggacgaaggcaaggtgaccccc
cgcttcgtggaagacctcggcgccgacagcctggaaaccgtggaactgatcatg
gaagacaaattcggcgtgaccattcccgacgaagccgccgaaaccatccgcacc
gccgcggtcgactacatcgacaacaaccag
>ORF00058 conserved hypothetical protein
atgtcagatatgaatgacgttgcccccccgaccttctgtcccgtgtaccgcgcc
gtgttgcaggaaaaatgggtgctgcacatcgtccgcgccctgctggggagcgaa
ttcaacgagctggcccgcgccgtgggcggctgcaacagcgccaccctgacgcag
gagagcctggaagacctgggcatcatcgtcaagcgcaccgaagacggcggcggc
gcccgcagcgtgtactcgctgacccctgccggacaggaactccagaccgtgatt
atcgacgcctgggcgcgcgcgcacctcagcgaatccgagccgacgcgctgcgtg