Final answer:
PCR is crucial for DNA fingerprinting because it can amplify a specific DNA sequence from minimal starting material, enabling the generation of enough DNA for profiling and comparison.
Step-by-step explanation:
One reason why the polymerase chain reaction (PCR) is so useful for DNA fingerprinting is its ability to amplify a specific region of DNA from a very small sample, sometimes as little as a single cell's worth. This is particularly helpful in forensic cases where only trace amounts of DNA are available at a crime scene. PCR can produce millions of copies of the target DNA sequence in just a few hours, which is essential for creating a DNA profile that can then be compared against samples from suspects or databases.
PCR's specificity comes from the use of primers that selectively bind to the DNA sequence of interest. The heat-stable enzyme Taq polymerase then extends these primers to create new strands of DNA in a cycle that repeats numerous times, exponentially increasing the amount of the DNA region focused on. Such amplified DNA can be used for analysis in genetic diseases detection, paternity testing, and sequencing, making PCR a versatile tool in molecular biology and diagnostics.