DNA
The DNA File
Much of the hope for solving the mystery of Alexandra Wiwcharuk’s murder lies in the potential if the DNA evidence recovered from her body.
Collecting and quantifying DNA evidence is a slow, painstaking process that bears scant resemblance to the instantaneous results produced in dramatic TV programs such as CSI.
First, there is a distinction between two types of DNA:
The search for and processing of DNA evidence as a potential tool to identify Alex Wiwcharuk’s murderer during the decades-long investigation, is itself a kind of chronology of the development of DNA testing in police work.
The Alexandra Wiwcharuk DNA case file summary
Interview: Karl Hummel
Karl Hummel has been involved with the DNA evidence of the Alexandra Wiwchauk case since the mid-1990s. At that time he was the forensics expert at the RCMP lab. When he retired he joined Molecular World Inc. in Thunder Bay, Ontario as Director of Marketing. Molecular World Inc is the only DNA laboratory in Canada that does DNA profile using both nuclear and mitochondrial technologies for a total of 4 different profiling methodologies. ( Read Karl’s PowerPoint presentation on Forensic Nuclear and Mitochondrial DNA)
Below is a partial transcript of an interview with Karl Hummel conducted by fifth estate producer Theresa Burke.
HOW HE APPROACHES HIS WORK:
Do you get emotional or get your hopes up when a sample comes in to be tested?
Absolutely not. With each sample that comes in I feel hopeful. Not hoping for a match, but just hoping that we get a result. Either way. If we’re excluding someone, that’s meaningful as well. That means the police don’t have to go down that road. But we do have a profile and if we were ever to get a match then the DNA profile would have been extremely helpful to the file that there’s a match to that. Then the person would have to explain why that sample is in this location. Because I look at it in a strictly scientific perspective and after I’ve given the information back to the investigators, it’s the call of the investigator and the prosecutor.
HISTORY OF LAB WORK DONE ON THE ALEX W. CASE:
At RCMP:
Initially, the work started with just a few exhibits. That grew into a number of exhibits starting in 1994. The work was on the things that were originally collected at the crime scene, including some of the material seen on the lab table in Sask Police Station in 2004. I remember the very first exhibit that was examined, I had to issue a note that said no human DNA was detected.
1994 and PCR:
At the time, 1994, we were one of the first labs in North America to go ahead with PCR – Polymerase Chain Reaction. Another name for PCR is “Amplification” and the process looks at specific regions along the DNA molecule and I am looking for a variation in the length of DNA. How it is done is through a biochemical process wherein regions of DNA can be copied accurately and it will then yield a visible fragment of DNA. Those fragments vary according to length or size and then it is looked at on many different locations along the DNA molecule. The DNA is now in a sufficient amount to determine what fragment of DNA is there. The length of the fragment at that locus and a number of other loci. Routinely the RCMP uses a technique called “Profiler Plus” and it looks at 9 different locations for length. The tenth place that it’s looking for is a sex typing. So there are really 10 locations.
So in 1994 the RCMP was just getting into PCR and we were just starting to do case work in it. I was the first one, myself and another fellow in the lab in Winnipeg, were the first to use PCR.
Then more and more exhibits came in. It was important to try other exhibits because we were trying to find the stranger profile, but it was also important to get a profile of the deceased so we would know the stranger profile if we found one. We finally got a complete profile from some pubic hair that had been previously collected from the deceased.
1994 to 2001 approx.:
The case came back to me at least 6 times with different exhibits coming in. Over the years I remember writing up about 6 reports on this file. The last report I wrote up would have been in 2003. I recall in this file there was basically a lot of limited amount DNA. So often my reports would be “there was DNA of an insufficient amount for the RCMP to be able to process”.
About 2004:
In 2004, Sgt. Phil Farion sent a number of items to us for re-testing. The RCMP at that time (and still I think) did not do male profiling tests. That was when I told him that there are other laboratories that have other techniques that are more sensitive. One of them is “Y-STR” or “Y-Filer”. It’s a male DNA profiling system. To obtain an STR profile there are various kit names. Y-Filer looks at 9 sites, “Identifiler” looks at 15, but they do the same job. What is really neet about Y-STRs is that you can have pools of material from the female victim, and just a trace of male, so their DNA material is mixed up together, but with Y-STR, because it only finds the male, you can have up to 1000 x the amount of female material and it will still pull the male. And it will give you the profile of a single source male profile. Then I sent the objects back to him and it was up to him, as the client, to send it to another laboratory of his choice.
The most sensitive profiling technique that is available today is mitochondrial DNA profiling. It will produce a profile from as little as 2 mm of shed hair fragment with no root.
KARL THEN RETIRED FROM THE RCMP AND BEGAN WORK AT MWI:
There are some techniques not available in the RCMP labs which can be found in the private labs. While I was still at the RCMP the following work was done at Molecular World: Using some shed hairs from which one couldn’t extract a nuclear profile but they could certainly get a mitochondrial profile from it which they did.
Now, even when there is no human DNA detected, there’s a separate process where you can still go forward for mitochondrial DNA because what is not being detected is nuclear DNA, but mitochondrial DNA is a separate type of DNA, which can also be profiled.
2004 Work:
I heard the results that were obtained by Molecular World in 2004. I was still at the RCMP lab at the time, and I believe we got a lab report from MWI that explains some of that.
2004 Exhumation of the Body:
There was an exhumation and there was further exhibits sent to the RCMP labs.
That’s when they started collecting DNA from suspects, or family members of dead suspects.
STATE OF THE ART:
Even just a few years ago, MWI had just three DNA profiling technologies, but now we have a fourth and that fourth one is called Mini-SDRs. It works very well on obtaining a nuclear DNA profile on something that we couldn’t obtain a profile from before – like for example a found human remain. Before these would have to be processed through mitochondrial DNA but Mini-SDRs have been successful on found human remains that have been a number of years old. And to obtain nuclear information about it, means that it can be tracked through the database. We do it for the FBI too.
A ROUGH GUIDE TO EVOLUTION IN EARLY DNA TECHNOLOGY:
ABO Blood Groupings – early ’90s.
RFLP – First Generation of DNA typing.
PCR – Next DNA typing.
Then PCR changed and you could get more information with less DNA.
