Fig. 3.

Diagram of the microsphere-based competitive hybridization assay format. Left: In the absence of target DNA, the biotinylated competitor oligonucleotides hybridize to the allele-specific probe-coupled microsphere sets. The hybridized microsphere sets are labeled with streptavidin-R-phycoerythrin, resulting in 100% signal. Right: When target DNA is present, the biotinylated competitor oligonucleotides hybridize to the target DNA instead of the allele-specific probe-coupled microsphere sets. The target DNA/competitor oligonucleotide hybrids are labeled with streptavidin-R-phycoerythrin, resulting in a reduction of signal on the allele-specific probe-coupled microsphere sets.