The FASTA format is used for representing both sequences of nucleic acids and amino acids. Since the one-letter code for nucleic acids largely overlaps with that for amino acids considerable ambiguities exist when reading FASTA files. As far as I could find out there is no standardised information on the type of sequence available in the header line.
Is there a recommended way for automatically distinguishing nucleic acid and amino acid sequences?
Interesting anecdote about
fasta
format by Bill Pearson (inventor) here: C: Was FASTA ever popular?