Cadaveric blood cards: Assessing DNA quality and quantity and the utility of STRs for the individual estimation of trihybrid ancestry and admixture proportions

As part a body donation program, blood samples were collected and stored on untreated (non-FTA) blood cards. The blood cards were evaluated in terms of DNA preservation and STR typing success with resulting profiles assessed with special consideration given to profile matching for positive identification and biogeographic ancestry estimation. While STR profiles were successfully generated for all samples, results indicate that the time interval between date of death and sample collection have an impact on DNA quantity and quality. There is a statistically significant decrease in relative fluorescent unit (RFU) values with increasing time interval between date of death and sample collection, indicating degradation in the blood card samples related to the post-mortem interval prior to sample collection. The STR profiles were used to estimate ancestry and admixture using the program STRUCTURE, demonstrating utility of these markers beyond individual identification purposes, with caveats for application based on population history.