Y Chromosome STR Typing: A Distinguishing Tool for Exclusion in a Casework of Sexual Assault

The sexual assault cases are on a rise in India’s capital Delhi (approximate fivefold increase in last 10 years) and so are the cases where men are falsely implicated for the same. Many cases go unreported owing to the social stigma attached. There have been cases where women misused these laws for personal gains [1]. Hence, any sexual assault case should be investigated carefully and impartially so as not to miss a single piece of evidence. We present a similar case study where the crime scene showed signs of violence. The presence of Y-peak on Amelogenin locus in Identifiler STRs in vaginal swabs of victim raised doubt of case being positive but Y-Filer STR helped in distinguishing the male contributor from the alleged accused. This conclusion strongly indicates the power of Y-STRs in forensic DNA analysis –it not only helps in identification of perpetrator but also in exclusion of the innocent.