In DNA fingerprinting, hybridised DNA fragments are detected by 

In DNA fingerprinting, hybridized DNA fragments can be detected using autoradiography. Autoradiography is a technique that involves exposing a photographic film or a phosphor screen to a source of radiation, such as radioactive isotopes or chemiluminescent markers. In DNA fingerprinting, the DNA fragments are often labeled with radioactive or fluorescent tags during the hybridization step.

• DNA samples are separated by gel electrophoresis to create distinct DNA fragments based on their size.
• The separated DNA fragments are then transferred to a membrane (usually a nylon membrane) using a technique called Southern blotting.
• The DNA fragments on the membrane are hybridised with a complementary probe. This probe is typically a single-stranded DNA or RNA molecule that is labeled with a radioactive isotope or a fluorescent tag. The probe will bind to the complementary DNA sequences on the membrane.
• After hybridisation, the membrane is exposed to X-ray film or a phosphor screen. If radioactive labels were used, the emitted radiation from the labeled DNA fragments exposes the X-ray film. If fluorescent labels were used, a specialised camera detects the emitted fluorescent signals.
• The exposure to radiation or the fluorescent signals captured on the film or screen results in a pattern of dark bands or spots, which corresponds to the location of the hybridized DNA fragments.
• By analysing the pattern of bands or spots on the autoradiograph or fluorescent image, scientists can compare DNA samples and determine if they match or if there are differences in the DNA fragment sizes, helping in various applications like DNA profiling, paternity testing, and forensic analysis.