Overview of a multiplex oligonucleotide ligation-PCR (MOL-PCR) assay. The workflow is illustrated for 1 target, with the described MOL-PCR being a 20-plex assay. However, a MAGPIX device can discriminate up to 50 different microsphere sets and hence up to 50 different targets. Optimisation of the MOL-PCR assay was attempted for several parameters and the green boxes indicate those parameters which had a major influence on the signal-to-noise ratios, as has been elaborated in the text. gDNA: genomic DNA; SAPE: streptavidin-R-phycoerythrin; see text for more details.