It seems hard to believe that two weeks ago Carolyn and I were sitting at the Interpol’s HQ in Lyon, France where we attended the 7th International DNA User’s Conference. Thanks to the generous sponsorship of the OSF-SA, Carolyn and I were able to attend this fascinating forensic DNA conference where I not only had the opportunity to present the provisions of the new DNA Bill in South Africa to the international forensic DNA community, but where we were able to learn more about the latest developments in this technology and hear from other countries about the status of their DNA databases and the laws and regulations which govern their databases, some interesting case studies, research papers as well as debates around misunderstandings of ethical issues oft raised around DNA profiling in a forensic context.
Vanessa Lynch & Carolyn Hancock arriving at Interpol's HQ in Lyon, France to attend the 7th International DNA User's Conference
Three particular presentations stood out for both Carolyn and I, namely: Advances in DNA investigations delivered by Prof Manfred Kayser; the latest DNA analysing device called Rapid DNA which is capable of producing a DNA profile directly from a sample within 90 minutes and the highly entertaining joint presentation given by Judge Arthur Tompkins and Dr Simon Walsh discussing the use of DNA profiling in a court of law. There were over 40 different presentations relating to forensic DNA , given over the course of the three days, but I have provided a brief summary of three of our favourite presentations below, as we are sure you will find them as interesting and exciting as we did.
The Keynote presentation delivered by Prof. Manfred Kayser from the Netherlands spoke around the issue of enhancing police operations through the advances in DNA investigations. Prof Kayser calls himself a ‘curiosity driven scientist’ and certainly through the research he is doing, it’s not hard to see why. The first advancement he discussed was around the issue of male specific Y-STR’s (short tandem repeats). As we know, it is difficult to differentiate between different male DNA profiles when a crime scene sample contains more than one DNA profile. These are commonly referred to as ‘mixed profiles’. The research into this area is taking place around looking at mutations present in the DNA profile which will help identify which profile belongs to which suspect. Instead of looking at more markers on the DNA profile, Prof Kayser suggests looking at the ‘mutation rate’ present in a DNA profile — in other words, if you have a marker with a high mutation rate it’s easier to distinguish between related males. Instead of using the current DNA profiling kit called ‘Y-filer’, current research is around developing new kits which use rapid mutation STR’s called RM Y.STRS. If this research results in a useable kit which does indeed differentiate between different male profiles in a mixed profile, this will certainly be useful in South Africa where the incidence of gang rape is so high.
Another fascinating advancement Prof Keyser discussed was the ability to identify the cellular origin of a sample. This is useful when the biological source of the sample is unknown. For example, if the clothing found at a crime scene contains a crime scene stain, it may be useful in an investigation to show if that source is semen, saliva or blood. Prof Kayser submits that they will soon be able to differentiate between biological sources as varied as saliva, ‘touch DNA’ (i.e., skin cells), blood, hairs, blood, menstrual blood, semen and vaginal secretions.
Waiting for a bus outside Interpol's HQ
Currently we are not able to establish from a DNA sample, how old it is, which would help indicate when the crime was committed. We are also not able to say at what time of the day it was deposited. This however may soon be possible as research is being conducted by looking at the melatonin and cortisol in a DNA sample to determine the time of day and age of that sample.
These advancements may all be well and good, but often one only has a single, precious DNA sample from a crime scene to work with, and in that case, because the amount of DNA is so limited, all of these tests would not be able to be performed. Prof Keyser reports that this issue may be overcome with the use of what he calls a ‘DNA Chip’ which takes a snip from one DNA sample and allows many different test to be performed using a single DNA chip.
Exciting stuff, and certainly in South Africa, these types of advancements would greatly enhance police investigations.
The issue of back logs and delays is an oft spoken about subject, and South Africa is not the only country where complaints are levelled at our Forensic Science Labs for delays in processing DNA samples… Imagine now if a law enforcement agent (as they are referred to in the USA – i.e. a police officer) was able to take a sample from an arrestee, pop it into a machine and send a request to securely submit the resultant DNA profile to the DNA Database within 90 minutes of loading that sample. This may sound farfetched, but ‘Rapid DNA technology’, as it is commonly known, is very real. And we were there to prove it. During a tea break, Carolyn and I submitted our DNA saliva samples to a Rapid DNA machine, and 90 minutes later were emailed our DNA profile! Whilst this technology is still being rolled out and is only capable of analysing 5 samples per run, in those instances where a quick result is required, this would be priceless. The advantages of this technology are that it can be performed by nontechnical users outside of the lab, i.e., police officers, there is no manual processing of the sample, the machines do not require calibration or data interpretation and it literally provides out of the box functionality. Oh, and it also doesn’t matter what type of sample is dropped into the cartridge!
What to do for an hour and a half in Lyon... hmm... Shopping? Sightseeing? Create a DNA profile?... Oh, absolutely YES please! Vanessa and Carolyn had the wonderful chance to submit their DNA samples to be tested in the new rapid DNA analyzer... 90 minutes later their profiles were ready! Simply amazing!
The last but by no means least of the presentations over the course of the three days was the highly entertaining joint presentation by New Zealand Judge Arthur Tompkins and Australian Forensic Scientist Dr Simon Walsh entitled ‘That’s the defendants DNA!’. This lively debate discussed the issue of probabilities and the way in which scientists express the probability of a defendant having the same DNA profile as the crime scene profile, in court. As we well know, the weight of admissibility of any type of evidence is based on certainty, and if evidence is expressed as a probability, it may lead some to think that because it is not expressed as a certainty, its admissibility is thereby negatively affected. Dr Walsh has had firsthand experience of this in court where DNA evidence despite being presented as a probability so remote (i.e., one in an octillion chance of two people having the same DNA profile) led it to be dismissed because it was not expressed as a ‘certainty’. Dr Walsh then looked at how discriminating DNA is as evidence, and the fact that with the advances in technology in this
Vanessa and Carolyn enjoying a quick break outside the Interpol headquarters with fellow guest speaker Tim Zolandz of the FBI (CODIS Missing Persons / International Progam Manager).
arena, the probabilities of two people having the same DNA profile are even smaller. In other words, if the probability or likelihood of another person having the same DNA profile as that of the crime scene sample, are one in an octillion which is 1,000,000,000,000,000,000,000,000,000 i.e. ten to the forty-eighth power, and there are only around 7 billion [7,000,000,000 i.e. ten to the power of nine] people in the world, then the weight of admissibility in respect of that evidence, you will agree, is extremely high!. Dr Walsh has suggested then that the way a probability as high as this is expressed in court should be changed and perhaps instead of expressing it in probabilities one should simply say there is more chance of you being hit by a meteor or eaten by a shark than there is of having the same DNA profile of another person. A leap of faith needs to be taken by scientists to express it as a certainty then, because the science is robust enough to allow for it. But these are issues of law, and Judge Arthur Tompkins reckons that in the words of Albert Einstein, if you can’t explain it simply enough then you don’t understand it well enough! As a Judge, he acknowledges that the likelihood ratios are getting bigger and bigger the more loci we use to identify a person through DNA profiling. But what he can’t understand is why the forensic experts won’t just say that IS the defendants DNA! He questions why they won’t simply do this and whether they are legally liable to do so now because the science is robust enough to allow for it.
7th International DNA User's Conference delegates
So: why won’t scientists take the next step? Perhaps it is because the statistical analysis has not simply answered the question the justice system is asking and that is: is this proof beyond reasonable doubt that it is the defendant’s DNA?
Simply answered, yes it is.
They are not seeking the scientific or statistical answer. They are asking is this proof beyond reasonable doubt that it does. This high standard of proof in a criminal court of law as opposed to absolute proof, is enough for all other forms of evidence, so should be enough for DNA too, which is probably the most reliable form of evidence available today!
So the question is: Are you sure?
And if the scientists are sure, why don’t they simply say: yes, I’m sure?
So if as a forensic scientist, and if you are sure, then you can say that you are sure.
And you should say you are sure!
Sounds a bit like Dr Seuss, which to me always made sense anyway!
The above three presentations were just some of the highlights of the three days spent listening to over 47 countries present over 40 subjects in this fascinating field. Not only did we enjoy every one, but the camaraderie and friendships that were renewed and made, were very special.
The Interpol Conference is unique insofar as it is a relatively small group of people passionate about their work and the advances in this technology, who are able to mix on both a professional and social level too. Every evening Carolyn and I were joined by different people from different countries where we shared our stories over French food and wine, and many laughs.
Vanessa and Carolyn with Susan Hitchin, Forensics Sub-Directorate at Interpol
It was with sad hearts that we said goodbye to everyone on the last day, and to the beautiful city of Lyon, where hopefully we will be invited to participate in the next and 8th International DNA User’s conference.
Thank you OSF-SA for enabling us to participate in this incredible forum.
Vanessa Lynch
