Y-STR analysis of digital and/or penile penetration cases with no detected spermatozoa

This forensic casework trial involved Yfiler® testing samples from 47 digital and/or penile penetration cases where the medical examination had occurred within 48 h of the alleged incident and no spermatozoa had been detected following Sperm Elution©. 30% of these cases yielded at least one Y-STR profile comprising three or more alleles per profile and 21% yielded at least one Y-STR profile of ten or more alleles per profile. This trial further investigated the persistence of male DNA in different case types, the location of samples submitted for testing and whether samples from different locations benefit from being combined prior to testing. The data supports the use of Y-STR profiling to provide scientific evidence to investigate whether the alleged sexual activity had occurred as well as to obtain probative evidence in spermatozoa negative penetration cases.