Describe the typical steps of genetic fingerprinting.

• A. DNA is extracted from the sample; DNA cut with restriction enzymes; DNA fragments separated by electrophoresis; transfer to membrane; probe with labeled DNA; detection; pattern unique to individual
• B. DNA is synthesized de novo and used to identify individuals
• C. DNA is amplified by PCR and sequenced
• D. DNA is converted into proteins to compare function

Answer: (A)

Genetic fingerprinting relies on generating and comparing patterns of DNA fragments that vary between individuals. The typical workflow starts with extracting DNA from the sample, then cutting it with restriction enzymes that recognize specific sequences. These enzymes produce fragments whose lengths differ among people due to genetic polymorphisms. The fragments are separated by size using gel electrophoresis, creating a visual banding pattern. The bands are then transferred to a membrane and probed with labeled DNA that binds to the fragments of interest; after detection, you see a pattern of bands corresponding to fragment lengths. Because the combination of fragment sizes is unique to an individual, this band pattern can be used to identify or compare samples. This describes the classic RFLP-Southern blot approach; many modern methods use PCR to analyze specific loci (like STRs) instead of the full digestion-and-blot workflow, but the underlying idea of comparing fragment patterns remains.