Genes of aggressiveness – a mitigating circumstance?
The Italian court recognized the lawyer's arguments based on the results of genetic testing, which revealed the defendant's genes associated with aggressive behavior, and reduced the prison sentence for murder by a year. This is the first officially recorded case in Europe of changing a court decision under the influence of behavioral genetics data. However, the experts to whom the representative of Nature asked for advice, question the scientific validity of this decision.
Algerian citizen Abdelmalek Bayout, who has been living in Italy since 1993, was convicted in March 2008 of the knife murder of Colombian Walter Felipe Novoa Perez, who lived in Italy. According to the defendant's testimony, the victim insulted him by speaking out about the makeup (circled with black pencil eyes), which the defendant applies for religious reasons.
At the trial, Bayut's lawyer Tanya Cattarossi drew the court's attention to the fact that her client could have been mentally ill at the time of the murder. After reviewing the results of three psychiatric examinations, Judge Paolo Alessio Vern i agreed that the defendant's illness was a mitigating factor and sentenced him to 9 years and 2 months in prison – in the absence of this factor, Bayut would have received about 3 years more.However, at the appeal hearing in May this year, the judge of the Court of Appeal in Trieste, Pier Valerio Reinotti, demanded that forensic experts conduct a new independent forensic psychiatric examination.
As part of this examination, a molecular neuroscientist from the University of Pisa, Petro Petrini (Pietro Pietrini) and a cognitive neuroscientist Giuseppe Sartori (Giuseppe Sartori) from the University of Padua conducted a series of tests and identified anomalies in the structure of the brain in the defendant, visible in the images obtained during brain scanning. In addition, Bayut revealed variants of five genes associated with aggressive behavior, including a gene encoding an enzyme that metabolizes the neurotransmitter monoamine oxidase A (MAO-A). In 2002, scientists at the Institute of Pediatrics at King's College (London, UK), working under the guidance of geneticist Terry Moffitt, found that low levels of MAOA expression are associated with aggressiveness and criminal behavior of young people who were physically abused in childhood.
When compiling the report, the experts came to the conclusion that the defendant's genes cause his tendency to aggressive behavior in case of provocation.
Based on the results of genetic testing, the judge reduced the term of the Bayute for another year, arguing that the defendant's genes explain his aggressiveness in stressful situations. When delivering his verdict, the judge noted that he considers the evidence based on the level of MAO-A in the body to be particularly convincing.
The decision was made in September, but it became public only a month later, after the publication of the story in the local newspaper MessaggeroVeneto.
An unbiased view of "genetic evidence"However, forensic medical experts and geneticists consulted by the Nature representative question the possibility of using existing scientific data as a basis for the conclusion formulated in the psychiatric examination submitted to the court.
According to Giuseppe Novelli, a forensic expert and geneticist from the University of Tor Vergata (Rome, Italy), scientists do not yet know how the entire genome functions and what possible protective effects other genes have. Therefore, tests for individual genes, such as MAO-A, are useless and expensive.
Moffitt adds that one of the problems is that the effects of the MAO-A gene manifest themselves differently in representatives of different ethnic groups. In 2006, a study conducted in the United States showed that former victims of child abuse with high levels of MAOA are less likely to commit violent crimes, but only if they have a white skin color. This pattern does not apply to "colored" children.
If the accused has African roots, this raises the question of whether this gene really affects his behavior. However, Petrini and Sartori did not test the ethnicity of the Bayute. In response to a question posed by a representative of Nature, Petrini said that in this case, talking about the ethnicity of the defendant is inappropriate. He claims that the accused does not belong to any of the "colored" ethnic groups described in the 2006 study. In addition, according to him, MAO-A is just one of the candidate genes analyzed as part of the examination.
Other genes, including the gene encoding the serotonin transporter, are also associated with various stress responses. However, they also demonstrate wide ranges of dependence on environmental factors. According to Nita Farahany from Vanderbilt University (Nashville, Tennessee), who specializes in legal and ethical issues related to behavioral genetics and neuroscience, in fact, behavioral genetics as a science does not yet exist. At the present stage, scientists cannot explain only the patterns concerning large populations, but not the behavior of individuals.
The lawyer insists that all data concerning the mental health of her client be duly considered by the court. She states that her client is obviously unwell and all issues that will allow the judge to make the right decision require careful study.
Since the "Stephen Mobley case", considered by the US court in 1994 – the first case in the world when the defense demanded to test the accused for MAO-A deficiency – lawyers around the world are increasingly trying to use MAO-A deficiency and similar genetic factors in the course of building the defense of the accused. Farahani regularly updates the database of sentences handed down in the United States, and, according to her, over the past five years, lawyers have tried to use genetic evidence to confirm the defendant's predisposition to aggressive behavior, depression or drug or alcohol abuse in at least 200 cases. In the UK, at least 20 such cases have been recorded over the past five years.
So far, the vast majority of such attempts have failed in court, and only a few of them have influenced the sentences handed down in US courts. Usually judges tend to reject the idea that a person is unable to make the right choice because of their genetic characteristics.
There is an opinion that an increase in the consideration of such cases can lead to genetic determinism (the idea that genes determine human behavior) in criminal cases.
According to Steve Jones, a geneticist at University College London, 90% of all murders are committed by people with the Y chromosome, that is, men. Does it follow from this that men should reduce their prison terms by default? At the same time, a lot of people have low levels of MAOA, but not all of them rush at others with a knife.
Farakhani also draws attention to the fact that such genetic evidence can be successfully used by the prosecution as an argument for tougher punishment, indicating the hereditary "depravity" of the accused and his danger to society.
There is a lot to argue about this, and it is completely unclear where the "golden mean" is, which judges should focus on in such cases.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on Nature: Lighter sentence for murderer with 'bad genes'.
02.11.2009