Sunday, February 8, 2009
Kiwi Calling: Australia Sends Forensic Evidence To New Zealand For Low Copy Number DNA Testing In Murder Investigation
"allows the genetic profiles of suspects, victims or witnesses to be 'uncovered' even when there is only a tiny amount of biological material present, sometimes as small as a millionth of the size of a grain of salt. The technique amplifies these tiny DNA fragments when it is believed that a suspect may have transferred DNA through touch, like the residue believed to have come from cells such as skin or sweat left in a fingerprint."
The problem: the technique can produce unreliable and false results. Indeed, as I noted in one of my previous posts, "[s]ince this technique was launched in 1999, it has been consistently doubted in the scientific community, and it has thus only been used in the U.K., the Netherlands, and New Zealand." Moreover, the U.K. actually suspended its use of the technique in 2007 after its use falsely connected Sean Hoey with the Omagh car bombing.
In other words, there is significant skepticism across the globe as to whether low-copy number DNA testing is scientifically reliable. And all of this makes a recent decision by Australia troubling, in my opinion.
On August 16, 2007, the body of Corryn Rayney was found buried in Perth's King Park in Australia. Over the ensuing eighteen months, detectives hunting her killer have come up empty, prompting the WA police to send forensic samples to New Zealand for low-copy-number DNA testing. Specifically,
"It is understood police sent several pieces of Rayney forensic evidence to New Zealand for LCN testing after WA’s PathWest science centre did not find any DNA on the items. Police refused to comment on this but a spokesman defended the technique, saying it was an 'investigative tool used in many jurisdictions.'"
Really? Based upon the information I posted above, I have to question how the spokesman is using the word "many." And it appears that several individuals in Australia are skeptical about the use of the technique. According to Curtin University DNA profiling expert Professor John Wetherall, LCN analysis is less reliable than conventional DNA profiling. "The problems with it are that any contaminating DNA from another human are also amplified and it is much harder to interpret the profile," he said. "It is more prone to technical problems."
Meanwhile, Murdoch University Professor David Berryman said if used properly, the technique could be a good investigative tool but that it was "not robust enough yet to help convict people." And Law Society senior vice-president Hylton Quail said the society had great reservations about the technique, which he claimed was not reliable and should not be admissible in WA courts as evidence.