Single-base extension (SBE) is a method for determining the identity of a nucleotide base at a specific position along a nucleic acid.
Using a DNA polymerase, the oligonucleotide primer is enzymatically extended by a single base in the presence of all four nucleotide terminators; the nucleotide terminator complementary to the base in the template being interrogated is incorporated and identified.
The method was invented by Philip Goelet, Michael Knapp, Richard Douglas and Stephen Anderson while working at the company Molecular Tool.
This approach was designed for high-throughput SNP genotyping and was originally called "Genetic Bit Analysis" (GBA).
Illumina, Inc. utilizes this method in their Infinium technology (http://www.illumina.com/technology/beadarray-technology/infinium-hd-assay.html) to measure DNA methylation levels in the human genome.