Techniques Involved in DNA Fingerprinting: Isolation, Quantification, PCR, Genotyping, and Analysis

The primary objective of forensic DNA fingerprinting is to establish the relatedness between the questioned samples and reference samples with absolute certainty beyond any reasonable doubt. This sophisticated and robust technique however requires a series of methodologies and procedures which are to be followed by the forensic scientists to obtain an accurate result. The procedures of DNA fingerprinting have accelerated through a series of major stages of technological advancement. It began with an initial methodology called “restriction fragment length polymorphism (RFLP)” crossing the stages of “minisatellites” or VNTR analysis and currently advancing through the stages of “microsatellite” or STRs and SNPs. Similarly the instrumentation processes involved also changed from horizontal gel to vertical gel system to automated analyzers consisting of sensitive microcapillary arrays with laser-based detection system. Quality softwares are now available for data analysis and generation of user-friendly reports. Even though the techniques involved in DNA fingerprinting vary greatly from laboratory to laboratory throughout the world, the basic concept remains the same and is represented here.