SAK Backlog Reduction
Recognizing the impact of untested sexual assault kits across our country, Signature Science is dedicated to supporting the criminal justice system’s efforts to address the backlog. Our Forensic DNA Laboratory has optimized workflow processes to deliver efficient and comprehensive analyses, scalable to meet the expanding outsourcing needs of government agencies. Using advanced techniques for DNA recovery, automation, and mixture deconvolution. We offer the most probative screening and DNA analysis strategies, resulting in timely generation of CODIS-searchable profiles. Our data management and deliverables software, STACS-CW, provides traceability and chain of custody documentation to improve data defensibility, and the data deliverables facilitate an efficient data review for CODIS eligibility at the NDIS laboratory.
Cold Case SAKs
Advancements in DNA analysis technologies have the potential solve sexual assault cold cases. Increased sensitivity and mixture deconvolution capabilities mean that for cases wherein testing has been completed in the past and returned a result along the lines of “inconclusive” or “no DNA present,” repeat testing could yield different, probative results. Our experts will work with you to discuss the details of your sexual assault cold case, including past testing, and suggest a testing plan aimed at case resolution.
Unidentified Missing Persons
Our accredited laboratories apply the same advanced technologies used to identify a criminal to help medical examiners, law enforcement, and federal government agencies identify nameless victims of violent crimes. Our validated FGG methods and workflows allow our experts to generate DNA profiles from many of the challenging sample types associated with an unidentified missing persons case (e.g., bone, teeth, hair).
Multiple Contributor Samples
DNA evidence collected from crime scenes is rarely single-source. In fact, samples can often contain DNA from multiple individuals. This occurs, for example, when a weapon has been handled by more than one person or when both victim and perpetrator DNA are present in a sexual assault case. These multi-contributor samples, or mixtures, are more complex to interpret than a single-source sample and require specialized analytical approaches.
Advances in laboratory methods, probabilistic modeling and biostatistical software have significantly improved the interpretation of mixed DNA samples. Today, these tools allow laboratories to extract more meaningful information from complex evidence, supporting criminal investigations and legal proceedings. Signature Science works closely with our clients to evaluate DNA evidence, develop an appropriate testing strategy, and apply validated mixture interpretation methods across forensic DNA casework and Forensic Investigative Genetic Genealogy (FIGG) cases.
Multiple Contributor STR Mixtures for CODIS — For suitable multi-contributor STR profiles, Signature Science’s analysts use STRmix™ probabilistic genotyping software to support interpretation. Suitability is determined following sample data review and is based on the quality of the sample and number of contributors present.
Two-Person SNP Mixtures for FIGG — Mixed DNA samples have historically been ineligible for FIGG because genealogical databases require single-contributor SNP profiles for upload. Signature Science now offers a validated approach for resolving SNP mixtures containing two contributors, enabling deconvolution of the major contributor SNP profile for genealogical searching.
Experts at the Center for Advanced Genomics, Signature Science’s in-house Forensics R&D engine, partnered with scientists from the National Biodefense Analysis Center (NBFAC) to develop, test, and validate the MixDeR mixture deconvolution software within our accredited laboratory. This capability improves analysis outcomes for challenging samples, including those encountered in cases of sexual assault and homicide.
Cold Cases and Challenging Samples
Not every criminal will leave behind a wealth of DNA, and not every crime scene provides ideal samples for DNA testing. To support your mission to solve every case, we have developed and validated methods for obtaining DNA profiles from samples containing minimal amounts of DNA, and those subject to the most challenging conditions.
We offer validated extraction methods (shell casings) and FGG workflows for challenging samples (bone, teeth, hair, adhesive tape), and those subject to challenging insults, including burning and surface decomposition.
Related Services: Casework Services | FGG | Spent Shell Casings