DNA or RNA segment tagged with a radioactive molecule is called

Probe is a defined nucleic acid molecule that can be used in molecular hybridization procedures to identify specific nucleic acid sequences that are complementary to it, by virtue of a label carried by the probe. The label may be radioactive or non-radioactive. Nucleic acid probes have a wide range of applications such as in the detection of microorganisms in clinical specimens, in food and water samples, in the detection of genetic diseases, etc.