A transmitting system and a method of transmitting digital broadcast signal are disclosed. The format takes advantage of the alternate renditions feature of the OCF of the EPUB\xae specification and includes both a ShockWave Flash based rendition and a HyperText Markup Language, Java Script, Cascading Style Sheets based implementation. Labelled nucleoside triphosphates matching the variable nucleotide are added and the incorporation of a label into the detection step primer is measured.