Microsatellites, also known as short tandem repeats (STRs), account for 3% of the human genome and have been associated with a number of disorders. More de novo mutations occur in each generation because of them than from any other variation, although their importance in naturally occurring diseases like autism and neuro developmental disorders has not yet been investigated. The core of forensic DNA profiles are STRs. The sterile nature of PCR necessitates the use of gloves, autoclaving, sterile settings, and DNA and D Nase[1] free reagents. An experiment's negative control aids in the detection of contamination. DNA sequences with short tandem repeats (STR) have become commonplace, emphasizing the importance of examination. Although validation is crucial for forensic samples that comprise mixtures, the introduction of multiplexed reactions has made STR analysis easier in case work. Genetic analysis of STR loci has proven to be the most accurate way to identify biological components in forensic investigations and human remains. The utilization of primer sequences to differentiate between sequences and the capacity to distinguish across over lapping size ranges are two advantages of STR amplicons. Although contamination within farmed cell lines continues to be an issue, contamination across species and within individual species happens in considerable percentages.