If your SAM or BAM file contains identifier information and you want to calculate read counts for a specific feature, you can use this field to specify the unique variable identifying the feature.
Note: SAM files typically do not contain this information. In most circumstances, you should use the parameters on the Summary tab for calculating count data.
Note: Some SAM files do not have headers. If your SAM file does not have headers, you can still specify a feature variable by typing VARn (where n is the column number of the desired variable) in the text box.
For example, if your SAM file has no headers, but you know that the desired feature is listed in column 5, type VAR5 in the text box, as shown below:
