The Effectiveness of Forensic Genetic Genealogy Techniques for Black, Indigenous, and Persons of Color

Familial searches using 13–20+ short tandem repeats (STRs) are sufficient to provide linkages to full siblings and parent-offspring pairs. However, more distant relationships, such as to first, second, or third cousins and beyond, cannot be detected without additional genetic markers. This has led to the prominence of genetic genealogical and related methods being applied to unsolved forensic investigations. Using microarrays or DNA sequencing, hundreds of thousands of single nucleotide polymorphisms (SNPs) can be leveraged to detect distant relatives using genealogy databases. Many factors can impact the performance of forensic genetic genealogy, including, but not limited to, input data quality, database size, and the number and genetic distance of cousin matches within the database. The composition of genetic admixtures in genealogical databases has been described as skewing predominantly Northern European, raising concerns about racial equity in forensic genetic genealogy. However, continuous migration and mixing of historically distinct groups have resulted in increased genetic admixture in the United States. Genetic admixture, as characterized by biogeographic ancestry calculations, is unlikely to be captured in self-declared ancestry, which relies on subjective and social concepts of identity. This study aims to assess the effectiveness of forensic genetic genealogy techniques for persons identified as Black, Hispanic, and Native American. In Phase I, volunteers will provide a DNA sample and self-reported ancestry of themselves, their parents, and grandparents. De-identified samples will be submitted to Othram, mimicking unidentified human remains cases. Othram will attempt to re-identify donors by uploading obtained profiles to genealogical databases used by law enforcement. Performance will be evaluated by considering the number of DNA matches and their genetic distance (in centimorgans) to the donor DNA. Investigation of shared family lineage using tree building will also be conducted. Any discrepancies between self-reported ancestry and computed biogeographic ancestry will be reconciled. Anthropological analysis has traditionally been used to estimate ancestry from human remains, and so in Phase II, we will evaluate human skeletal samples submitted from individuals estimated to be Black, Indigenous, or Persons of Color (BIPOC) based on anthropological assessment. Investigative genetic genealogy performance will be determined as described for Phase I. Discrepancies between anthropological assesments of ancestry compared to biogeographic ancestry calculations will be investigated. Phase III will involve coalescence of the data generated in the first two phases to demonstrate the efficacy of genetic genealogy methods for use in ways that would be inclusive of BIPOC persons.  CA/NCF