Short tandem repeat analysis for human identity testing.

Short tandem repeat (STR) typing has become the workhorse of modern forensic DNA analysis. The most common form of STR typing uses laser-induced fluorescence detection of dye-labeled polymerase chain reaction (PCR) products following capillary electrophoresis (CE) size-based separation. This unit describes the techniques and marker systems most widely used around the world in constructing criminal DNA databases and conducting forensic casework. In addition, these same STR loci and multiplex PCR assays are commonly used for paternity testing, missing persons, and mass disaster investigations. Both autosomal and Y-chromosome STRs are discussed in the context of their various applications. Interpretation issues surrounding degraded or mixed DNA specimens as well as tri-allelic patterns and variant alleles are also illustrated. Finally, future technologies and DNA marker systems are briefly explored relative to the state-of-the-science today.