Single base primer extension genotyping

Figure 12.2. Single base primer extension. This patient is heterozygous for this Ato C substitution. The labels from both ddNTPs can be detected in this sample. In the case of a homozygous genotype, only one of the labels would be detected. Detection might be through ELISA, fluorescence, FRET, or FP.

MALDI-TOF mass spectrometry has recently proven an attractive means to analyse single base extensions. Several thousand samples can be analysed each day, because each analysis requires only a few seconds. Furthermore, within each sample, multiple independent loci can be simultaneously analysed. With this internal multiplexing, tens of thousands of SNP genotypes can be obtained each day. Reagent costs are comparatively low, because there are no signal molecules in the assay and the primers are unlabeled and comparatively inexpensive. Because... 

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