Which of the following is NOT an early application of RFLP?

The correct choice highlights that gene therapy is not considered an early application of Restriction Fragment Length Polymorphism (RFLP). RFLP technology emerged primarily in the 1980s and was quickly adopted for various applications involving the analysis of DNA by cutting it into fragments with restriction enzymes, followed by sizing the fragments through gel electrophoresis.

Identifying microorganisms, paternity testing, and forensics were all initial uses of RFLP. The technique proved particularly useful in differentiating between microbial strains and for establishing genetic relationships, such as confirming biological relationships in paternity cases and identifying suspects or victims in forensic investigations through DNA profiling.

Gene therapy, however, is a complex method that involves the introduction, removal, or change of genetic material within a person's cells to treat or prevent disease. Although it may incorporate various molecular techniques, including those based on RFLPs at later stages, it was not one of the early uses of the technology.