Forensic typing of short tandem repeat markers on the X and Y chromosomes

Short tandem repeat (STR) markers are the cornerstone of forensic identity and kinship testing. Markers located on the X and the Y chromosome can complement those found on the autosomes, which are commonly used in laboratories today. The distinctive inheritance pattern of the sex chromosomes affords advantages to the investigation of family pedigrees required by mass disaster victim identification or missing persons cases, as well as mixed samples typically recovered in sexual assault crimes. This review aims to provide an overview of how X and Y STR markers are currently being used in forensic laboratories, including the applications which target their use, the markers and multiplexes facilitating recovery of this genetic information, and the tools available to interpret the resulting data. Emerging research topics are considered as well as issues requiring further study for both marker systems.