Courtney Hall from the University of North Texas Health Science Center presented at the Nanopore Community Meeting 2022 on “STRspy-ing hidden variation in forensic DNA profiles using the MinION device.” Hall spoke about how short tendem repeats (STRs) are often used as the “gold standard for human identification in forensic investigations” due to their variability in individuals. An STR profile is typically an electropherogram with a peak. This approach sometimes lacks the resolution needed, leading to “hidden variation.” For example, there could be a heterozygous locus. Hall and team developed an approach to use the MinION device by targeting STRs of interest. They used a commercial amplification system and barcoded the products. The STRspy workflow takes the reads and maps them to the database you construct. STRspy then predicts the genotypes based on the normalized read counts. Hall and team compared their results with STRspy to a typical approach. With a 30 cycle approach they obtained complete concordance with the dataset. They have recently expanded to Y STRs. Now they can multiplex numerous samples without compromising detection. Hall explained that they are working on updating their database to include several sample types: buccal, blood… Their workflow will be very useful and is being improved.
