The Science Weeks have been closed at the University of Navarra with the conference "Science against crime", given by the professor of Biochemistry Iñigo Izal. In total, more than 750 students of ESO and Bachillerato from 15 centers in Navarra have participated during these days in the workshops "Touch Physics, Chemistry and Biology" and have performed experiments in Microbiology; they have been able to visit the Science Museum and attended some of the four talks on science and popularization open to the public.

The last of these, "Science against crime", has served its author to explain, through some curious historical cases, how using DNA manipulation techniques it is possible to determine the origin of biological samples. "The story begins in 1968," says Professor Izal, "with the murder of Claire Joseph. In those years little could be done with a sample of biological origin in a criminal investigation, apart from determining the blood group. In the talk we used this case because, thanks to the fact that the blood groups of the victim and the murderer were the rarest in the population, the perpetrator of the crime was caught".

"The idea with the lecture is for students to understand that for a DNA analysis to be useful, we need to determine or measure "something" that makes us unique. That is, that its frequency in the population is so low that my genetic fingerprint cannot be shared by anyone else," he says.

From the first DNA fingerprint to modern analysis

This breakthrough came in the 1980s, with the description of the main DNA manipulation techniques. "In the conference we told the story of how Sir Alec Jeffrey succeeded in making the first DNA fingerprint, using the blood of a colleague of his and her parents. From that moment on, several lawyers began to contact him and genetic analysis entered the field of forensics, through an immigration case and another case involving the murder of two teenagers in which, for the first time, a person guilty of murder was arrested thanks to DNA analysis", explains the professor of the Faculty of Sciences of the University of Navarra. At the end of the conference, he explained to the students how modern DNA analysis is currently carried out by the scientific police.

The more than 750 students of ESO and high school who have participated this year in the activities of Science Weeks of the University of Navarra came from the schools Luis Amigó, Ikastola Paz de Ziganda, Dominicas, IES Plaza de la Cruz, Jesuitas, Teresianas, IES Padre Moret, IES Sangüesa, Santa Luisa de Marillac, CIP Donapea, IES Caro Baroja, Notre Dame, IES Berriozar, Liceo Monjardín and IES Basoko.