Fig. 1.

Schematic representation of a PCR/LDR/universal array assay. In the example shown, the assay is used to detect the identity of a single base variant (A/C) within a gene of interest. The target gene is amplified using gene specific PCR primers. The PCR amplicon is subjected to an LDR reaction using two upstream primers, one ending in T (complementary to the A allele) with the complement to zip-code 2 attached to its 5′-end and the other ending in G (complementary to the C allele) with the complement to zip-code1 attached to its 5′-end. If the allele present in the sample is C (as shown), then only the “T” primer will ligate to the downstream fluorescently labeled primer. When the ligation products are hybridized to the universal array, a positive signal is seen at zip-code address 1