Can the “warrior gene” explain aggressive and violent acts so that lawyers base their defenses on that in courts? Can genetics determine whether your marriage will be a long-lasting companionship? What about alcoholism, depression or autism? To what extent are we the product of our environment or the expression of our genes? While the nature versus nurture debate has been ongoing for centuries, the recent advances in genetics and genomics seem to shift the balance towards inheritance rather than the effect of our surroundings. We looked around whether it is justified, especially when it comes to its use in legal disputes.

The accused are innocent, lock up their insides

Do you remember the episode from House M.D when he tricked the team and the hospital into treating a death row inmate? It turned out that the patient had adrenal gland tumor, which released adrenaline at random intervals resulting in a violent rage. At some point, House even suggested that the fourth victim might have been killed during such an eruption of anger. At the end of the episode, his fellow doctor, Foreman argued that he would testify at the patient’s appeal, while House believed many other people with a similar condition managed to control their rage, thus biology could not absolve a murderer.

Turning to reality, let’s look at Bradley Waldroup’s case. He shot his wife’s friend eight times and attacked his wife with a machete. The woman survived, the man didn’t. Waldroup admitted responsibility for the crimes; prosecutors in Tennessee charged him with murder and attempted first-degree murder. If guilty, a death sentence looked likely. Then came forensic science: it turned out that the accused had an unusual variant of the monoamine oxidase A (MAOA) gene – referred to as the “warrior gene” due to its association with antisocial behavior and impulsive aggression. A forensic scientist testified that Waldroup’s genetic makeup, combined with the abuse he had experienced as a child, left him at higher risk of violent behavior. Finally, the jury decided that instead of murder, he committed voluntary manslaughter – and it seemed that biological factors, “bad genes” played a role in the final verdict.

Although there’s an ongoing debate to what extent genetic and neuroscientific evidence plays a part in court decisions such as Waldroup’s, some scientists are worried that the trend to incorporate the latest scientific findings might be misleading. Genetics is still a relatively new area, and there are still too many blank spots about how genes work.

Source: www.inverse.com

From tabula rasa to freckle genes

Philosophers have contemplated for centuries about human nature: its components, its influencers or its (in)ability to change. Plato and Descartes suggested that certain things are inborn, or that they occur naturally regardless of environmental influences, while other well-known thinkers such as John Locke believed in what is known as tabula rasa, which suggests that the mind begins as a blank slate. According to this notion, everything that we are and all of our knowledge are determined by our experience. 

The nature versus nurture debate took a turn when Charles Darwin’s half-cousin, Francis Galton read his theory of evolution – and wanted to apply it to humans. He believed that desired human traits were hereditary, and humans can be improved through selective breeding. Later on, his genetic determinism alongside with eugenics – the enhancement of humans by genetics – became associated with the racial policies of the Third Reich, and the theory became unwelcome after the Second World War.

The renaissance of genetic research started with the completion of the Human Genome Project, which gave a boost to diving deeper and deeper into the secrets of life. Scientists gradually discovered genes which are responsible for the color of our eyes, for freckles, dimples or curly hair. While there has always been widespread acceptance that genes determine our physiology for good and bad, much greater controversy has surrounded the subject of our psychology – our behavior and personality traits. That’s what behavioral genetics is after.

Source: www.nationalgeographic.com

Where does behavioral genetics stand?

The field is an interdisciplinary effort to establish causal links between genes and animal (including human) behavioral traits and neural mechanisms. For determining which features could have their roots in genetics and which are shaped by the environment, in many cases, researchers use twin studies. Already Galton studied the behavioral characteristics of genetically identical twins who were raised in different settings. Twin studies are still used to identify specific genes that can be linked to particular behaviors, but lately, methods of genetic and molecular techniques as well as whole-genome association are also applied.

As genetic analysis progressed, experts found that only a fraction of conditions, traits or behaviors could be traced back to one single gene, and characteristics are instead the result of multiple genes interacting with numerous environmental factors. In the case of neurological disorders, such as autism, researchers found that the inheritability of the condition is around 90 percent, however, they have had severe difficulties locating the set of genes and gene mutations which can cause the development of autism. Moreover, even pinning down the right genes does not mean automatically that those genes will be expressed in certain people – not to speak about the already mentioned environmental factors.

Awareness of these complexities has shifted researchers’ focus from individual genes to entire genomes, thus giving rise to the field of behavioral genomics. Through the advances in genome sequencing, in the future, there will be more and more studies in the area, and instead of specific genes, entire genomes will get the majority of attention from researchers. However, we have to note that the field and its findings are far from comprehensive at the moment – that’s why it is so difficult and dangerous to draw conclusions.

Source: www.health.clevelandclinic.org

Could bad genes cause alcoholism or unhappy marriages?

Most people encounter behavioral genetics when meeting sensational headlines preaching that scientists have found a particular gene or gene set responsible for a specific human trait – from alcoholism through sexual orientation or even the quality of marriage. In the case of booze dependency, researchers found 39 genes associated with the condition. 

When I uploaded my raw genetic data to Promethease, the analysis suggested that I have an SNP (single nucleotide polymorphism, the most common type of genetic variation among people), which causes me to process alcohol much better than others, while also another one which shows that I have a higher risk factor for becoming alcoholic. That’s somehow understandable since people who can process booze better have to drink much more than those who are knocked out after two glasses of wine. In spite of all these facts, I did not become an alcoholic, which is an addition to the argument that a behavior trait is not the direct consequence of a “bad gene” but the interplay of genetics and the environment. Nevertheless, I’m glad I’m aware of that genetic risk so that I can create the conditions to give as little room for it as possible.

However, many researchers do not stop at revealing the genetic secrets of certain conditions or psychological disorders but aim to dive deeper into human nature. Alan Sanders at North Shore University, Illinois, and his team identified individual genes that may influence how sexual orientation develops in boys and men, both in the womb and during life. Findings related to sexuality might cause changes in attitude towards the gay community and could finally put an end to the notions of being able to “cure” anyone from a specific sexual orientation. 

Scientific evidence for the genetically deterministic nature of that human trait – although not comprehensively proven yet – could mean in the future another tool in the hands of the LGBTQ community to strengthen their identity, however, it might lead to an interesting twist regarding marriages. A research team led by Binghamton University Associate Professor of Psychology Richard Mattson evaluated whether different genotypes of the Oxytocin Receptor gene (OXTR) influenced how spouses support one another, which is a key determinant of overall marital quality. OXTR was targeted because it is related to the regulation and release of oxytocin, which is a hormone associated with feeling love and attachment. 

www.goodhousekeeping.com

According to the key findings, husbands with a particular genotype, which other researchers associated with signs of social deficits, were less satisfied with the support they were provided – leading to less contentment regarding the entire marriage. Thus, while many might believe that marriage is a social construction entirely shaped by individual behaviors and customs learned from the environment, it might have a genetic component – and it might turn out in the long term that some people are genetically less “coded” for long-lasting companionship. That certainly needs further research though – just as one of the most exciting topics here: the source of human intelligence.

Precision education after pinning down the genes of intelligence?

Could randomly wandering thoughts be pinned down to specific genes? How do you even capture the essence of intelligence? What does it entail? And even if you determine its boundaries, how could the level of knowledge be measured objectively? We all know that the closest humans could get was the creation of the IQ test, but that has its own problems.

Nevertheless, philosophical problems never stopped researchers from trying their best. Chinese biotech giant BGI, started a project using their genome sequencing and analyzing capabilities to figure out the “source of genius”. The company collected 2,200 genomes of individuals with IQs over 160 (average IQ is said to be around 100), and the team will compare their genius genomes to a random selection of the population to see if they can isolate differences between the two. While BGI is well aware of the difficulties and controversies around the study, they are saying that “we simply wish to start the process of discovery, and believe that this is a good place to begin.”

Another place where similar efforts are underway is King’s College London with the lead of Robert Plomin, behavioral geneticist, who has provided more than a 1,000 genomes for BGI. He leads a long-term study of 13,000 pairs of British twins on the subject. His efforts already reaped some fruits. While until 2017, no gene had ever been tied to performance on an IQ test, since then, more than 500 have, thanks to gene studies involving more than 200,000 test takers. Results from an experiment correlating one million people’s DNA with their academic success are due at any time. Plomin says that in the future, parents will use direct-to-consumer tests to predict kids’ mental abilities and make schooling choices, a concept he calls precision education. 

Source: www.vox.com

However, we are far away from that – recent predictions are not highly accurate, and it willtake decades of research until that could become a reality. Of course, some companies cannot wait for that much and started to take a ride on the trendy genetic train.

Do genes reveal your perfect match or your intelligence levels?

MIT Review found that at least three online services, including GenePlaza and DNA Land, have started offering to quantify anyone’s genetic IQ from a spit sample. However, that’s far-fetched, to use the most diplomatic expression about those direct-to-consumer companies’ efforts. As of yet, you cannot tell the academic prospects of a child based on their genetic composition, no matter what certain DTC companies claim.

But that’s not only true for the link between genetics and intelligence. Some enterprises claim that if you want to know whether your kid is talented in football, how your grumpy moods are coded in your genes, who your perfect match is based on your DNA, you should just order a DNA test. No wonder that even Stephen Colbert joked about a company offering a wine selection based on your genes. As he said, he can smell “total bullshit” – and he’s right. There’s no scientific evidence for stating such direct linkages between certain behavioral traits and genetics. 

Back to square one: so should lawyers use geneticsin defense of the accused?

The brief response is: the time has not come yet to trace back violent, criminal behavior solely to genetic reasons. Forensic scientists are also only confident to say that a particular DNA composition coupled with a specific setting in which the defendant grew up could lead to an elevated risk of antisocial behavior. However, that is already a diluted opinion which should not have that much relevance in judging the case.

The reason why lawyers are pushing for it is the argumentation that if a defendant’s criminal behavior, rather than being determined by conscious choices, was driven by unconscious genetic predispositions to commit antisocial acts, the person may seem less responsible for the outcome and therefore less deserving of punishment. Thus, behavioral genetics, at least in principle, has become a tool for legal claims of reduced culpability and mitigated punishment.

And looking from a philosophical perspective – it might lead to the loss in the notion of freewill. What does it make of the human capacity to act if it turns out that our actions are only driven by a couple of genes in our cells? Where does it lead humanity if it turns out that freewill does rather exist in our socially constructed dreams, while deep down we are driven by the inherited DNA? 

Source: www.datarevenue.com

And some food for thought for further discussion: what do we make of the direction which might lead humanity down the path of “giving up” the notion of free will by saying that genes determine much more than we believed before – while at the same time humans are working on machines to give them more and more intelligence and eventually consciousness. How do we put up with that?