National Institute of Standards and Technology (NIST) researchers are working on a new approach to DNA matching that could enhance the capabilities of forensic investigators.
Jointly funded by NIST and the FBI, the research is aimed at moving beyond DNA profiling based on short tandem repeats, or STRs. This refers to a practice in which analysts look at the number of times a genetic code is repeated in a DNA sample; the repetitions are unique enough that they can be used to calculate the odds of a given sample being a match to another one, which is how investigators can be reasonably confident that DNA from a blood sample at a crime scene, for example, matches DNA collected from a suspect.
But in cases where only a very small amount of DNA is available, or if the DNA of multiple individuals has been mixed together in a given sample, a new, emerging methodology could prove helpful. This is called Next Generation Sequencing, or NGS, and is based not on the number of repeats of genetic code – the STRs – but on the information in the genetic code itself. It used to be that looking at such a fine-grained level of detail wasn’t cost effective, but technological advancements have changed that, allowing researchers to look at DNA samples in even greater detail.
NIST’s researchers have now established a system for statistical NGS-based DNA analysis that revolves around 27 genetic markers, and have published their research in the Forensic Science International: Genetics journal. This is just the beginning of the transition to NGS-based DNA analysis, but as it catches on and forensic labs adjust their processes to incorporate the new methodology, it could lead to more effective investigative work, with the potential to help police catch criminals and to help the justice system exonerate the falsely accused.
July 25, 2018 – by Alex Perala