Want to keep learning?

This content is taken from the Pompeu Fabra University Barcelona's online course, Why Biology Matters: The Genome and You. Join the course to learn more.

Skip to 0 minutes and 12 seconds Maybe the most difficult part of that is to take the evidence that you have as expert and to convince the judge. How do you deal with such a sophisticated analysis and, both genetic and statistical, with a naive person in science as a judge, for example, how you explain a probability to a judge?

Skip to 0 minutes and 38 seconds This, I would say, that besides all the technic aspects of our work, I would say that main challenge of our work is the communication of probability of the evidence, because we express it in our reports in a probabilistic way, but it is very difficult when you find or when you’re on trial on the court to explain this in those terms, so we have always (a very usual) to find examples from the real life that could help to understand the meaning of our results.

Skip to 1 minute and 20 seconds It is not just the coincidence between two genetic profiles, it’s the probability that this genetic profile belongs to the suspect or to the victim, in this case, in front of the probability of that these genetic profiles do not belong to them but it’s from a random person of the population. This, in some aspects of our reports, of our explanations, is very difficult to deal with people, yeah, with judges, with lawyers, even not only the court but also the jury and they… you have to use all the tools with good examples to try that they understand the meaning of the probability of the evidence. Taking consideration that sometimes the lawyers are going to misunderstand it, on purpose.

Skip to 2 minutes and 18 seconds Of course, this is it. Yeah, yeah. They would try to… or maybe they don’t understand this because you don’t have explained it in the correct way but also, they sometimes… they understand what they are interested in, and this… yeah, this is an… it’s a constant fight for us but more or less I think that we can… yeah, we have general success in the way of explaining all this kind of results to the court. A difficult position to be objective in a scientific way. How the experience or the long tradition of the very well know the TV series, as CSI, is influencing your job?

Skip to 3 minutes and 10 seconds Well, nowadays, fortunately, this is not so strong as it has been in the beginning, the first seasons of this kind of series or even movies and so on. This was even called de CSI effect because, well, we found a group of investigators… well, it’s very curious because they know about everything, they are experts in everything and well, the problem was mainly that some of the techniques that they show on TV they are not real, or they are impossible to perform. And the second big problem for us was the time they spent by resolving the case. It was a real time of twelve hours, this is for us impossible.

Skip to 4 minutes and 7 seconds We are maybe weeks or even months… that takes us to give, yeah, to make a report because we have enough results or good results to make it. So, this was the first years of these series. This was quite, yeah, difficult for us because even we have received phone calls from judges saying us why are we so late because on TV they resolve the cases in twelve hours, you know? But it’s over.

Skip to 4 minutes and 41 seconds Okay, so today we have seen how biology, genetics, DNA, is being used in this case for a very applied field: forensics for identification. Thank you very much. Thank you very much too.

Conversation with Àlex Pifarré. Part 3

Àlex Pifarré, officer at the National Institute of Toxicology and Forensics of the Ministry of Justice in Barcelona.

The use of DNA in forensics is a subject that spans several disciplines: genetics, because it concerns various regions of the genome; statistical genetics, which are used to calculate the probability of a given hypothesis; and law, as the evidence obtained from the DNA is presented in court.

Share this video:

This video is from the free online course:

Why Biology Matters: The Genome and You

Pompeu Fabra University Barcelona