Sexual assault evidence presents some of the most challenging extraction problems in forensic science. Sperm cells require disruption of their disulfide cross-linked nuclear protamines, a job traditionally done with DTT, mercaptoethanol, and chaotropic salts. Those chemicals are also potent PCR inhibitors.

Exymes Application Note 013 compared forensicGEM Sperm directly against a bead-based competitor across four dilutions: 1:10, 1:100, 1:1,000 and 1:10,000. The Exymes chemistry uses Acrosolv, a reagent that lyses sperm without DTT or chaotropic salts, in a closed single-tube workflow on a standard thermal cycler.

At the 1:10,000 dilution, qPCR data showed substantially higher DNA concentrations across all replicates for the Exymes method. STR profiling at that dilution produced usable profiles with the Exymes chemistry; the competitor had no peaks above 100 rfu.

At 1:1,000 dilution, the Exymes profiles also showed better heterozygote peak balance and intracolour balance.