Genetic Markers for Sex Identification in Forensic DNA Analysis

The ability to determine the sex of an individual based on DNA evidence can be crucial in instances such as identification of victims of mass disaster, missing persons investigations, and sexual assault cases. The Y chromosome marker amelogenin is currently in widespread use for determination of chromosomal sex of an unknown DNA donor and differentiating the relative contributions of male and female DNA in a mixed forensic sample. However, many cases of the failure of the amelogenin marker to correctly determine the sex of DNA donors have been reported, causing the usefulness of the amelogenin marker in forensics to be questioned. In this paper we review use of amelogenin as a marker for sex identification in forensics and describe four additional Y chromosome markers, sex-determining region Y (SRY), Y-encoded testis-specific protein (TSPY), locus DXYS156, and steroid sulfatase (STS). The SRY, TSPY, DXYS156, and STS markers each have properties that could be used for developing more rigorous methods of testing forensic DNA samples for a Y chromosome or the presence of specific reproductive or secondary sex characteristics.