Final answer:
Restriction enzymes are crucial in the RFLP process, which allows for the differentiation of DNA samples by creating unique DNA "fingerprints" based on restriction enzyme digestion patterns.
Step-by-step explanation:
Restriction enzymes are needed in the process known as Restriction Fragment Length Polymorphism (RFLP) analysis. This technique depends on the fact that DNA from each individual contains many segments with unique sequences, and these sequences can contain restriction enzyme recognition sites. The presence of genetic variation, or polymorphism, means that individuals have DNA with different restriction enzyme cleavage sites. During RFLP analysis, the DNA sample is first digested with a restriction endonuclease, which recognizes and cleaves specific DNA sequences. This results in different individuals having distinct banding patterns when their DNA fragments are separated through agarose gel electrophoresis, creating a DNA "fingerprint." These banding patterns arise due to variations in the length of DNA fragments generated because of the presence (or absence) of certain restriction sites. RFLP can thus be used to differentiate between DNA samples based on these observed fragment length differences, which is invaluable for genetic mapping, forensic science, and paternity testing.