Genomic sequences are commonly stored in FASTA formatted files. A file is in FASTA format if the first line of the file begins with the character '>' followed by a comment describing the genomic sequence. Subsequent lines of the file contain the genomic sequence. Normally, in a FASTA formatted file, each line containing genomic sequence information is the same length, except possibly the last line.
Here is an example of a FASTA formatted file.