It is well known that forensic DNA typing by short tandem repeat (STR) analysis has a risk of being affected by low levels of contamination. Contamination is defined as the inadvertent addition of an individual's DNA during or after collection of the evidence sample and may thus occur both at the crime scene and in the laboratory. Especially low template (LT) DNA analysis, i.e. the analysis of less than ~100pg input DNA, suffers from amplification of alleles not associated with the crime stain while in samples with high amounts of input DNA low levels of contamination can remain undetected.
Vandewoestyne M, Van Hoofstat D, De Groote S, Van Thuyne N, Haerinck S, et al. (2011) Sources of DNA Contamination and Decontamination Procedures in the Forensic Laboratory. J Forensic Res S2:001. doi: 10.4172/2157-7145.S2-001