Labeled substances that have specific affinity for the transferred proteins, DNA or RNA. They can be radioactive, chromogenic, fluorogenic, or enzyme conjugates of antibodies. Lectins, protein A and complementary DNAâ€™s or RNAâ€™s are among the common probes used. See Tag and Label.
Particular nucleic acid (DNA or RNA) molecules which can be used to detect specific nucleic acid sequences that are complimentary to the probes. The probes are labelled in some way so that, when hybridised with the complimentary nucleic acid, the probe can be detected. Probes are often labelled with either radioactive isotopes or fluorescent chemicals.