Detection of specific DNA sequences with short biotin-labeled probes

We have developed a simple, general synthesis of nonradioactive DNA probes in which biotin is attached to the 5'-terminal phosphate of an oligodeoxyribonucleotide 16 bases long via an ethylenediamine or hexamethylenediamine linker. The products are stable under normal hybridization conditions. They hybridize to target DNA as efficiently as the underivatized oligodeoxyribonucleotide. Color development, using a commercially available kit, is complete within 3 hr using the biotin-detection method. The sensitivity of detection of homologous DNA with a probe to which biotin was attached via a hexamethylenediamine linker is about one-tenth of that achieved overnight by autoradiography with the corresponding 32P-labeled probe.