Forensic Science International 94 (1998) 65–71 Evaluation of a decontamination protocol for hair shafts before mtDNA sequencing * Els Jehaes, Anja Gilissen, Jean-Jacques Cassiman, Ronny Decorte Center for Human Genetics, University of Leuven, Leuven, Belgium Received 2 December 1997; received in revised form 3 March 1998; accepted 12 March 1998 Abstract Mitochondrial DNA (mtDNA) sequencing is a powerful and sensitive method to identify the donor of shed hairs found at a crime scene. Because of the low amounts of DNA in shed hair and the sensitivity of PCR, contaminating cells (e.g. saliva, blood), sometimes present on these hairs, will be co-amplified. This will result in ambiguous sequencing results and might even lead to erroneous exclusions of suspects. We have evaluated a strategy for effectively removing saliva and blood contamination from hair samples. Unambiguous mtDNA results were obtained by incubating the hair samples in a differential lysis buffer (which contains no DTT) prior to DNA extraction. Since the nuclear DNA of the hair root is affected, this procedure should be restricted to hair shaft proportions.  1998 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Forensic science; Decontamination; Hair shaft; Mitochondrial DNA typing 1. Introduction Human hair is one of the most frequently found biological samples at crime scenes. Previously, forensic hair analysis was based on the microscopic comparison of evidence hair with reference hair from victim or suspect. With the advent of the polymerase chain reaction (PCR), DNA typing of hairs has become feasible [1]. Most human hairs recovered from crime scenes, however, are naturally shed hairs and do not contain a root. Amplification of nuclear DNA from these hairs is problematic because most DNA is located in the root cells. However, by amplifying mtDNA, which is present in high * Corresponding author. Tel.: 132 16 346077; fax: 132 16 345997; e-mail: ronny.decorte@med.kuleuven.ac.be 0379-0738 / 98 / $19.00  1998 Elsevier Science Ireland Ltd. All rights reserved. PII: S0379-0738(98)00052-8