The BED format is a text file format used to store genomic regions as coordinates and associated annotations. The data are presented in the form of columns separated by spaces or tabs. A BED file consists of a minimum of three columns: the names of chromosomes or scaffolds, the start, and the end coordinates of the sequences considered. The next nine optional columns contain annotations related to these sequences.

chr1 213941196 213942363
chr1 213942363 213943530
chr1 213943530 213944697

DNA sequences in FASTA format are required to generate background sequences. Each sequence in FASTA format begins with a single-line description, followed by at least one line of sequence data. The description line is distinguished from the sequence by the first symbol '>'.
Below an example shows two sequences in FASTA format:

>chr1 13257652 13257741
gccgccgccgccaacgctgctgctggtgcc
ttcgctcttcactgtcagtttcctgtttac
atcatcacttcccccctttgataaggcaaa
>chr1 40437905 40438036
gggaccgcagaatgctgcgctgatgcagtt
aaagagaaagaacgtcagggttaaggagca
aggccagagacactggggaaggtaaataag
agggctcacagctgggtatgagccagccaa
gctaactagtga

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