Discuss briefly how a probe is used in molecular diagnostics.

A probe is used in molecular diagnostics for labelling a gene or small fragment of genome segment. It is a RNA or DNA fragment which is used for labelling DNA sequences and for genomic mapping and sequencing. A probe is generally radio-labelled or fluorescent labelled and detected by various methods.

A probe is taken and it forms a complementary DNA with the normal (template) DNA but doesn’t attach to mutated DNA. Thus, it can be used for labelling of the mutated gene for molecular diagnostics.