Single-base extension

The Single Base Extension (SBE) is a biological reaction, which can follow after a PCR (Polymerase Chain Reaction).

The PCR Product is a DNA sequence which includes a SNP (Single Nucleotide Polymorphism). This DNA-Sequence is used as Template in a SBE. Another component for this reaction is a special primer, with a biotin - molecule at on side and a special base which is easier destroyable through UV-Light than other bases at the other side. In addition also a special SBE-Polymerase is given to the components of that reaction. That polymerase synthezises the primer on the template exact one base before the SNP. After this the polymerase synthezises a ddNTP according to the base pairing on the SNP. When finished its work, the reaction is over. After a SBE follows an SBE-Product-Purification and at the end a MALDI TOF MS to analyse which kind of SNP is in the DNA-Sequence.