Think of two brothers and a wealth jealously guarded by her father. One of the children known to be the most reckless, to get their hands on the money, do not hesitate to kill. It attempts to drop the blame on the other. To shed light on the crime, nothing better than to resort to DNA tests. But, surprise, the result just nail the guy angelic and unexpected: the few drops of blood found by police belong to him. The accusation has no more doubts. The jury seems to conduct a conviction announced. Yet, the miscarriage of justice lies in wait.
How come? The genetic evidence is considered the queen, the one that gives an almost infallible certainty involvement in a crime or helps to support the strangeness of the scene of the crime. Since it was introduced (the American FBI began using in 1988, his "invention" dates back four years earlier) has solved many cases and many obscure events of the past thanks to a re-reading techniques are then unavailable. The DNA tests, now famous thanks to TV, film and literature, he also saved the lives of 17 death row inmates in the United States, found innocent after being sentenced through the use of genetic analysis. The improvement of technology today promises greater accuracy and in a short time, perhaps next year, the American police can rely on devices able to read near real-time chromosomal profile of people detained.
The privacy issues are well known. But a recent scientific paper by researchers at a private company and the Israeli police seem to have dealt a severe blow to the ability to maintain the DNA as the sole and indisputable element of incrimination in a criminal trial.
has been shown that it is feasible to produce indistinguishable genetic tests in the laboratory, even without possessing organic material of the person in question: one has access to the "tab" of that individual kept in a database, either legal or medical. And the task is within reach of a biologist with no special skills. "You can easily manipulate the scene of a crime," he told New York Times <+corsivo> <+tondo> Dan Frumkin, lead author of the study, published in <+corsivo> Forensic Science International: Genetics <+tondo>. The purpose of Nucleix, the company he works for, is not entirely disinterested: the bio-tech company in Tel Aviv has made it a point to your test designed to distinguish true DNA samples from those "built."
Back to the two brothers. Just take a cigarette butt, a hair or a glass from which he drank to extract the DNA of the subject and create a sample to be put on a weapon or a ski mask in form of a sketch of a drop of blood or saliva. Do not even need a special skill, many biologists (if dishonest) may perform a similar operation without the need for special equipment. And could split the "work" anonymously between centers dealing with genetics, making orders over the Internet, sending and receiving the samples in the mail.
The key point is that Israeli researchers have sent weapons and other objects "dirty" laboratory used by the U.S. Justice and none of qualified technicians noticed nothing wrong with looking at the track. In one case, a woman's blood have been removed white blood cells (which contain DNA) were then added and it genetic fragments taken from the hair of a man. This finding, which is subjected to one of the most important centers in the United States, was typed without uncertainty as a male profile.
The findings of Frumkin and his colleagues were judged to be 'disturbing' by the American Civil Liberties Union: "The DNA appears to be more easy to spread onto the scene of a crime of the same fingerprints. And we are building a criminal justice system that increasingly relies on this technical evidence. " Some concern was expressed instead
by Peter Lio, a professor of Bioinformatics at the University of Cambridge. "Difficult" age "and" fragment "the DNA in the way usually looks at the crime scene - says -. Of course, today the technology is progressing so fast and allows more sophisticated manipulations. Requiring additional attention and research. For the benefit of DNA evidence, it should be remembered that it is possible to analyze the genetic profile of a person even mixed with 200 tracks of many individuals. "
agree Lucia Bianchi, Lawyer in Florence and an expert in forensic genetics: "In the case of the brothers, the defense would not have sold easily. We must consider the alibi, the way in which the tracks may have been left at a crime scene. And then there is not only the DNA evidence. Consider, for example, the trajectories of the splashes of blood. The gun must be tweaked to perfection. It is not enough sample with which the fake dirt. In short, counterfeiting seem very difficult. "
The fact remains that the DNA test has lost some 'of its aura of infallibility. Although the counter-move is just the authors of that study. Further analysis may find that the genetic sample is artificial (due to the phenomenon of methylation). But no laboratory in the world to run again ...
Amdrea Lavazza
Source: avvenire.it
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