LDR (Ligase Detection Reaction) is a ligation dependent methodology that, unlike LCR (Ligase Chain Reaction), involves only one pair of probes complementary to one strand of target DNA. Cycling in LDR results in linear amplification of the ligation product. This method can be used to confirm the presence of a particular SNP in a target sequence that has been amplified by another method (such as PCR). As with LCR, the method uses a high fidelity thermostable ligase that can discriminate against the ligation of mismatched probes, such as Taq DNA Ligase (NEB #M0208) and 9°N™ DNA Ligase (NEB #M0238).

For more information regarding ligase specificity and high fidelity ligases, visit “Substrate specificity and mismatch discrimination in DNA ligases”.