To solve this problem, we need to identify which of the given options is not required for any of the techniques of DNA fingerprinting available at present. Let's analyze each option:$\newline \bullet$Option 1: Polymerase chain reaction (PCR)$\newline$ - PCR is a technique used to amplify DNA sequences, making it a crucial step in many DNA fingerprinting methods.$\newline$ - It allows for the generation of large quantities of DNA from a small sample, which is essential for analysis.$\newline$ - Therefore, PCR is required for DNA fingerprinting.$\newline \bullet$Option 2: Zinc finger analysis$\newline$ - Zinc finger analysis is not a standard technique used in DNA fingerprinting.$\newline$ - Zinc fingers are protein domains that bind to DNA, but they are not directly involved in the fingerprinting process.$\newline$ - Therefore, zinc finger analysis is not required for DNA fingerprinting.$\newline \bullet$Option 3: Restriction enzymes$\newline$ - Restriction enzymes are used to cut DNA at specific sequences, which is a fundamental step in many DNA fingerprinting techniques.$\newline$ - They help in generating DNA fragments of varying lengths for analysis.$\newline$ - Therefore, restriction enzymes are required for DNA fingerprinting.$\newline \bullet$Option 4: DNA-DNA hybridization$\newline$ - DNA-DNA hybridization is a technique used to measure the degree of genetic similarity between DNA sequences.$\newline$ - It is not a standard requirement for DNA fingerprinting techniques, which typically rely on PCR and restriction enzymes.$\newline$ - Therefore, DNA-DNA hybridization is not required for DNA fingerprinting.$\newline$Based on the analysis, the correct option is Option 2: Zinc finger analysis, as it is not required for any of the techniques of DNA fingerprinting available at present.