Highly accurate and reproducible DNA analysis techniques are used routinely in forensic laboratories to generate results from forensic evidence, which may ultimately link a perpetrator to a crime scene or prove an individual’s innocence. Forensic scientists use commercial kits that detect specific biomarkers called short tandem repeats (STRs), which are comprised of repetitive sequences that occur within all populations at different frequencies. Detection of these biomarkers in DNA samples generates highly specific, precise, and reproducible data for the identification of a unique “DNA fingerprint” for each DNA sample.
Life Technologies STR kits combine sensitive PCR chemistry with the power of multicolor fluorescence technology to enable robust and reliable results for all human identification applications. The most recently released tools available to forensic analysts are GlobalFiler™ kits. The comprehensive technology within these kits enables forensic labs to take advantage of 6 dyes and 24 loci for reduced amplification time and increased discrimination power while allowing for the inclusion of more mini-STR markers for improved data recovery from degraded samples. Mini-STR markers are smaller regions of the same STRs, and they are used to increase the chances of collecting data when working with broken down or fragmented samples.
Since 1988, every US state has established a database of criminal offender DNA profiles. Twenty-five states have expanded their ability to solve and prevent crimes by including in their databases DNA profiles from felony arrestees. One result of the effectiveness of forensic DNA databases is the national trend towards creating investigative units that focus on resolving old unsolved crimes. Throughout the US, police are establishing specialized units that identify DNA evidence in old cases and input those DNA profiles into various databases to discover perpetrators. As these databases grow, so do the chances of identifying a perpetrator–even if a case is more than 20 years old.
The Innocence Project, a nonprofit organization that uses DNA technology to overturn the wrongful convictions of prisoners, helped to secure STR-based DNA testing for Herman Atkins eleven years after he was convicted in 1988 for the rape and robbery of a store clerk. The evidence helped confirm that someone other than Herman had committed the crime, and he was released from prison in 2000.
For Forensic or Paternity Use Only.
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Schellberg T, Oldroyd N, Schade LL (2013). HID in action: maximizing the power of forensic DNA databases with next-generation STR technology. Forensic News