The Cytoband file format is used to define the chromosome ideograms for a reference genome, and/or as of version 2.11.0 to create a cytoband track.

A cytoband file is a five-column tab-delimited text file. Each row of the file describes the position of a cytogenetic band. The columns in the file match the columns of the cytoBand table in the database underlying the UCSC Genome Browser.  These files are downloadable from the UCSC website as "cytoBandIdeo.txt.gz" for many genome assemblies, for example

Column Example Data Type Description
chrom chr1 string Chromosome
chromStart 0 integer

Start position in chromosome sequence

chromEnd 2300000 integer End position in chromosome sequence
name p36.33 string Name of cytogenetic band
gieStain gneg string Giemsa stain results. Recognized stain values: gneg, gpos50, gpos75, gpos25, gpos100, acen, gvar, stalk