[MUSIC] Hello, everyone. Welcome to this session on assessing the value of forensic DNA results. We are in the laboratory that is dedicated to DNA analysis. It is here that all students learn how to do DNA profiling. The lab is also used by our PhD candidates, so the room is used both for research and education purposes. During this week, we will discuss cases where DNA was said to have caused a miscarriage of justice. Based on international cases we will illustrate the potential aspects that one needs to consider when assessing the value of DNA found in a small quantity. We will apply the NC guidelines for evaluative reporting in the case at hand and see if the principles advocated allow to avoid misleading evidence. We will compare the situations where large quantities of blood are found to cases where low quantities of DNA is recovered. You will learn to contrast these two situations and discover what type of results can be expected and what methods allow a balanced and robust interpretation. In the first part of this week, Alex and Franco will present the case of the murder of Meredith Kercher, also known as the Amanda Knox and Raffaele Sollecito case. There are several aspects to this case. One important one being how the items were handled, and the possibility of pollution, aka contamination. You might wonder why we use this strange term, pollution, to indicate that the crime scene items were compromised by adding unwanted material. Why not simply use the term contamination? Pierre Margot, our former director, and a very important figure in Forensic Science, argues quite convincingly that the term pollution is better. But let us ask him directly why he is so adamant that we use the term pollution and not the term contamination. Pierre, could you tell us in a few words why it is important to distinguish pollution from contamination? >> Well, vocabulary is not important as long as you know what you are talking about. The problem in forensic science, we are borrowing words that are used in chemistry or biology. And there is a great confusion between contamination and pollution. Contamination is the background if you do an investigation on the scene of crime. This is part of the history of the place and that can be also something important for trace evidence. Whereas pollution would be something that you add afterwards. That would be by, say, the medical teams, the investigating teams, coming in without protection, and adding further confusion on the scene. So the notion of pollution is more negative than the notion of the background contamination, which is part of the history of the place. >> Thank you, Pierre. Now that you are familiar with the term pollution, let's see together the program of this week. As mentioned, the topic of pollution is an important facet in the case of the murder of Meredith Kercher. But this issue has been also encountered in the other cases that we will discuss in Part B. Therefore, in the first part of this week we will present the Amanda Knox and Raffaele Sollecito case. We will study how one should assign the value of DNA results when there is a very little amount of DNA. This will enable to demonstrate that very sensitive techniques require robust and ad hoc interpretation methods. Indeed, we will see that due to the small quantity, one will have more uncertainty due to artifacts or the presence of DNA of more than one person. That is what we call mixtures. In the second part of this week, you will understand that with minute quantities of DNA, stringent control procedures are needed on the crime scene and in the laboratory. Indeed, pollution, that is, you'll remember materials, such as DNA that is added due to careless handling, is an aspect one needs to take into account. One needs to acknowledge that pollution can happen anywhere in the process. Cases for example in Australia, in the United States of America, and in England have indeed shown that traces can be polluted on the crime scene, at the hospital by paramedics, and in the laboratory. It is thus essential to consider the possibility of pollution, especially when DNA is the essential and sometimes the only element supporting the allegation of a person's involvement in a crime. We will see together with Alex how to take into consideration the possibility of error due to pollution when assessing the results. This leads me to introduce the objectives of this week. They are as follow. First, you will understand how we obtain a DNA profile. And you'll be able to explain what a DNA profile is. Second, you'll be able to distinguish between DNA results that are obtained from a large quantity, and DNA results that were obtained with a very small quantity. So you will recognize phenomena, such as drop-in, drop-out, elevated stutters. Third, you'll be able to identify situations where one needs to take into consideration potential pollution. You'll be to explain why, if, and how one should account for possibility of error, an error that might falsely incriminate a given person. This week is divided in different videos and will be organized as follows. First, we will see together how one performs DNA analysis and what type of results can be produced. Then in part A, Franco and Alex will present the case of the murder of Meredith Kercher. And we will discuss how to assess the DNA results when the quantity is very small. In part B of this week, Franco and I will discuss specifically cases of DNA pollution, and we will see with Alex how one can account for error. In the conclusion, Christoph will discuss these cases in the light of the guideline. But before the presentation of these cases, let's go to the lab and learn how a DNA profile is obtained. [MUSIC]
