BCIT Forensic DNA Lab
This case study is an excerpt, DNA for First Responders: recognizing, collecting and analyzing biological evidence related to dentistry, taken from Chapter 8 of Forensic Dental Evidence: An Investigator’s Handbook (2nd ed): Elsevier (2010)
- https://www.elsevier.com/books/forensic-dental-evidence/bowers/978-0-12-382000-6
- Print ISBN 978-0-12-382000-6
- Electronic ISBN 978-0-12-382001-3
This case, which was completed at BCIT on behalf of the British Columbia Coroners Service, illustrates the impact that the addition of a mini-STR multiplex can have within a forensic laboratory process. In November 1970, during poor weather, a small, single-engine airplane with its sole male occupant crashed in southern British Columbia, Canada. Although the crash site was not far from the heavily populated Lower Mainland, it was in steep, heavily wooded terrain. The site remained undisturbed until 2007 when a surveyor stumbled across it. The coroner and police processed the scene and collected several skeletal elements, including a heavily damaged skull and portion of long bone.
Evidence from the plane provided a potential lead with respect to the identity of the pilot, but a DNA comparison to a putative daughter was required for confirmation. Even after exposure for 37 years to the harsh conditions of this area, usable DNA evidence was generated. Although no DNA was detected in two sampled molars, sufficient DNA was isolated from the long bone to proceed with DNA typing. An initial amplification with Profiler PlusTM yielded a partial (male) profile with two of the nine STR loci exhibiting drop-out due to degradation. Analysis and comparison to the daughter using kinship software yielded a combined likelihood ratio of 118. Additional testing with MiniFilerTM yielded a complete male profile with no drop-out observed at the eight STR loci amplified. Overlapping loci were consistent between the two DNA typing kits and the combined genetic data resulted in a total of 12 usable STR loci and combined likelihood ratio of 4953. The end result was a strengthening of the reported concluding statement from “strong” to “very strong” when describing the strength of the genetic evidence in favour of identification.
