Forensic Genetic Genealogy (FGG)

Our team of forensic scientists, bioinformaticians/data scientists, and genealogists, works closely with law enforcement clients to determine if their case samples are suitable for genotyping and compliant with the current U.S. Department of Justice policy on FGG DNA analysis and searching.

Criteria include, but are not limited to:

• Case involves an unsolved violent crime, and the candidate forensic sample is from a putative perpetrator, or unidentified remains of a suspected homicide victim (‘unidentified human remains’).
• The forensic profile derived from the candidate forensic sample must have been uploaded to CODIS, and subsequent CODIS searches must have failed to produce a probative and confirmed DNA match.

A checklist containing all the minimum requirements for the candidate samples will be provided as part of the initial request for candidate sample submission for FGG. Case review will conclude with a conference (via video or telephone) between Signature Science and a designee to report the conclusions of the review and to determine and authorize the final workflow on a case-by-case basis.

The current DNA input requirements are ≥ 0.05 ng/µL in a minimum volume of 10 µL for GSA and 0.04 ng/µL in up to 25 µL for Kintelligence. We currently require samples to be single source but there are some exceptions that depend upon the ratio of major to minor donor in the sample.

Candidate sample(s) (items and/or extracts) submitted for FGG are extracted (if necessary) and first quantified using the Investigator® Quantiplex® Pro Kit to ensure sufficient quantity and quality are present for genotyping. Depending upon quantity and quality and thorough discussion with Law Enforcment, the forensic scientists will help guide the best FGG service (GSA or Kintelligence) to use to obtain the best results for your sample(s).

The Infinium Global Screening Array is a genome wide genotyping method that provides ancestry, identity, and phenotype (hair/eye color) markers along with extended kinship markers. This method allows for higher sample throughput while maintaining low DNA input requirements.

Kintelligence, an integrated FGG solution based on next-generation sequencing technology, targets forensically relevant markers along with ancestry, identity, and phenotype (hair/eye color) markers to estimate kinship.

Each is optimized for degraded and low-input DNA samples from a range of sample types including blood, bone, buccal swabs, hair, teeth, semen, and touch DNA (e.g., tape and spent shell casings). Further, Signature Science has genotyped cremains and burned and surface-decomposed bone indicating the ForenSeq Kintelligence performs well with highly degraded remains, which can sometimes be challenging for array methods. 

Signature Science’s demonstrated successful genotyping with DNA input levels down to 0.2 ng, three orders of magnitude lower than the manufacturer’s recommended input of 200 ng.

Our GSA method is optimized for challenging and low-input DNA samples from a range of sample types including blood, bone, buccal swabs, hair, teeth, semen, and touch DNA (e.g., tape and spent shell casings).

Similarly, our Kintelligence method is optimized for degraded and low-input DNA samples from a range of sample types including blood, bone, buccal swabs, hair, teeth, and semen. Successful genotyping, eligible for GEDmatch Pro upload, has also been shown from degraded samples (e.g., bone) with various insults including cremation, embalming, and surface decomposition.

Microarray data are visualized and analyzed using Illumina’s GenomeStudio® software. The data generated undergo rigorous quality assessment, followed by data preparation and upload into GEDmatch for finding genetic relatives. Formatted data are uploaded into FamilyTreeDNA on a case-by-case basis. Additionally, upon request, data can be analyzed to provide phenotypic information such as biogeographic ancestry and hair, eye, and skin color.

Kintelligence workflow data analysis component is performed with the Verogen ForenSeq Universal Analysis Software, and long‑range kinship estimation in GEDmatch Pro informs the construction of a family tree.

Genetic genealogy research is performed on the DNA data output file(s) from the genealogical database(s) with the goal of generating leads for our law enforcement clients. Through this process, leads such as ethnicity composition, surnames, familial geographic locations, and DNA relatives may be reported. Each individual piece of information collected is considered a lead and is reported to our law enforcement client.

In the interest of solving more violent crimes, several organizations and nonprofits provide grant funding to law enforcement for FGG services. These funds can help subsidize the costs of advanced DNA testing methods, and help your agency solve its toughest cases. Start your search.