Lun added, “The results from NOCIt provide the probability for how many contributors exist in a sample. For example, it could say there is 60% probability that there are three contributors, 20% probability there are two contributors, and 20% probability there is one contributor. But it does so by considering multiple data points, thereby removing as much of the human factor as possible. I think we all would want to know that the evidence that is being presented at a trial is being handled and analyzed in a consistent way, and the results are not dependent on some subjective judgments that could have significant effect on what gets reported.”
Accurately assessing the number of contributors (NoC) in DNA samples is vital in forensic analysis. In a review paper as part of the 20th INTERPOL International Forensic Science Managers Symposium in 2019, internationally recognized forensic DNA analysis expert John Butler stated: “[a]ssessment of the number of contributors is a critical element of accurate DNA mixture interpretation.” The forensic domain currently uses repetitive sequences in the human genome called short tandem repeats (STRs). However, accurately predicting the NoC is difficult, especially when the samples contain large numbers of contributors. The technology Grgicak and Lun developed more accurately and fully identifies the number of contributors in a mixture than any existing method.
Grgicak and Lun tested the performance of NOCIt for their journal article in Forensic Science International: Genetics in 2020, using 815 experimental DNA mixtures consisting of one to five contributors, and damaged and undamaged DNA. NOCIt correctly identified the number of contributors in more than 90% of the experimental samples and corrected 28% of the incorrect estimations made by the best pre-existing method.
According to Grgicak, most often in forensic DNA analysis, the crime lab or the analyst will amplify the DNA using a polymerase chain reaction (PCR), which is a method to amplify specific segments of DNA by making billions of copies of particular DNA fragments or genes, which allows the analyst to detect and identify gene sequences using visual techniques.
The result of that laboratory process is called an electropherogram (a plot of results from an analysis done by electrophoresis automatic sequencing), which contains peaks that provides information about an individual’s potential identity. However, if many contributors make up the mixture of DNA collected from a crime scene, the electropherogram is very complex, with many peaks, and an accurate number of contributors can be difficult to infer by eye or when using other manual methods.
The collaboration between Grgicak and Lun was born in Boston; she was an assistant professor at Boston University Chobanian & Avedisian School of Medicine and he had just completed similar work in the Medard Lab at MIT. Their NOCIt technology, which they began working on together in 2011 while she was at BU and he was an associate professor at Rutgers-Camden, has the potential to streamline and improve the forensic DNA analysis process.
SoftGenetics, which has over 20 years of experience developing and supporting DNA analysis software to aid the forensic community, is excited to add their technology to its wide variety of genetic analysis software for both clinical and forensic applications, according to Director of Marketing & Product Management in Forensics & Fragment Analysis Teresa Snyder-Leiby. “By adding NOCIt to our products, we are now able to cover all the bases of forensic DNA analysis, as calculating the number of contributors is the biggest concern for so many labs.”
The Office for Research handled the negotiation and execution of the license.
“The Office for Research was extremely supportive through the entire process,” said Grgicak. “Any time we had a question, they responded, and they were very diligent in making sure Rutgers was represented well. Having the Office for Research as the conduit between the industry partner and the PIs was invaluable.”
Lun concurred. “We could not have done this without the Office for Research. Catherine and I both felt that we’ve got NOCIt to the point of maturity that we're comfortable with. The challenge was that we are not in a position to commercialize, and we've been looking for a partner to take the next step with the technology.”
“The technology developed by Catherine and Desmond has the potential to improve the DNA analysis process not only in the United States but also around the world, and we are proud to have worked with them to license it to SoftGenetics,” said Deborah Perez Fernandez, acting executive director for Innovation Ventures.