The Genetics of Human Behavior

Genetics is, relatively speaking, a very young science. After discovery of DNA and it's building blocks it stopped being solely statistical and psychological study of heredity. Ever since then it was given a third component in its labs - a microscope. So to speak. In simple words, we are now able to dive more deeply into the world of genes and their government of human body and behavior. Many genes are already identified in relation to how we act and interact with others and our environment. Let's discuss some of them that already earned cool nicknames in relation of what they are capable of or we suspect they do.

The mixture of genes we own are given to us by our parents, which they inherited from their parents who were gifted with the same from their own mothers and fathers and so on. What is finally our DNA composed of, basically defines us and not just our looks and physical properties but also our behavior. For example there is a 'wanderlust gene' some of us have it dominant that drives a person toward adventurous behavior and everlasting desire for travel and search for unknown. The other example is a 'warrior gene' that in many cases explains somebody's aggressiveness and violent behavior. There's even a 'god gene', a molecule identified with a power to direct a person to be superstitious and religious. Imagine what happens if these three genes become dominant in a single person who by the chance becomes the leader of a country with the worldwide influence?


In regards to human behavior, the main question is what has dominant influence, the environment or genetics of a person? The best results of course are given by statistical study of separated identical twins who after reunion shown many similarities in personalities even though they were raised in different families and environments. However we should not underestimate environmental influence simply because if behavior came to be the result of complex multiple genes doing, they could not have detectable effect due to environmental impact. For example even if you have a warrior gene, it's influence could be buried if you are raised in loving family without much violent disturbance from the others. Even more, in such scenarios it could help you with more positive influence than negative, for example in your sport's career it is always better to act with sort of allowed aggressiveness.

With disclaimer in mind of me not being a genetics scientist please find more info in referral links throughout this post and instead, in today's spirit, let me introduce half a dozen of cool identified genes or candidates in many cases, responsible for various human key behavior.

Wanderlust gene
DRD4-7R
The key word here is dopamine, a hormone and neurotransmitter responsible for many different features in our brain (including autonomous movement of muscles). However in this particular case, dopamine is released in hedonistic situations, when we experience something nice and pleasurable. The more hedonistic person we are, the smaller thing or event can trigger enough release of a dopamine in our brain, like taste of enjoyable food or reading a book or seeing a photo. Other people have lower sensitivity to dopamine and for those (up to 20% of population) who contain DRD4-7R gene which is a variant of DRD4 dopamine receptor, eating pleasurable chocolate is not enough to release level of dopamine in order to receive a hedonistic reward. These people always seek more from their environment, because they need more stimulation in order to hit a satisfying level of dopamine. If their environment is not enough they take risks and move to another, much like nomadic people do or all those large migration of people in the history who move to another area without obvious reason even though the environment they were initially inhabited was as good as the new one. If you ever said aloud that you like very much to travel to various different places no matter what, remember it might be DRD4-7R talking.


Refs:
https://www.telegraph.co.uk/travel/travel-truths/the-wanderlust-gene/
https://www.sciencenewsforstudents.org/article/explainer-what-dopamine
https://www.verdict.co.uk/drd4-7r-wanderlust-gene/
https://www.huffpost.com/entry/is-there-really-a-wanderlust-gene

Warrior gene
MAO-A
MAO (monoamine oxidase A) is the name of the enzyme which acts in nerve cells (neurons) of the brain as a recycling factor for neurotransmitters and in process of oxidation it brakes down serotonin, epinephrine, norepinephrine, and dopamine among all the brain chemicals it deals with. Signals transmitted by serotonin regulate mood and emotion, epinephrine and norepinephrine control the body's response to stress while we already know that dopamine controls physical movements. MAO-A gene is responsible for MAO regulation and in people who have a variant of the "warrior gene" (low-activity form of the gene called MAOA-L) less MAO is produced, which means that less of the neurotransmitters are broken down which in turn leave higher levels of unwanted neurotransmitters in the brain. For all we know from various past study, higher levels of these brain chemicals produce higher levels of aggression and as a result these people feel less or none empathy for others and they basically don't hesitate to use any form of anti-social behavior including violence to achieve their own goals whatever they are.


Refs:
https://en.wikipedia.org/wiki/Monoamine_oxidase_A
https://ghr.nlm.nih.gov/gene/MAOA#
https://www.psychologytoday.com/us/.../triggering-the-warrior-gene-in-villain-or-hero
https://www.sciencedaily.com/releases/2009/01/090121093343.htm

Creativity gene
COMT-DRD2
If you are able to produce something that is both novel, useful and closely related to human development whether it belongs to individual or societal level, you are among people with creative mind won on genetic lottery. Similar to the hedonistic process in our brain, according to several researches in previous decades, dopamine is also the key hormone responsible for creative process, more accurately dopamine levels in multiple brain areas enhance interaction between frontal and striatal dopaminergic pathways (dopamine neurons location in brain) which is believed to lead toward creative thinking and reward after something new is either achieved or produced. While responsible genes involved in dopamine transmission and generation of just enough dopamine levels needed for creativeness is still ongoing process, two genes are the most promising candidates - COMT and DRD2, both their single involvement in the process as well as in their prior interaction.


Refs:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3995040/
https://medicalxpress.com/news/2018-04-dopamine-producing-areas-brain-creativity.html
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4718590/

God gene
VMAT2
Unfortunately, due to the sensitive subject, research in regards to spirituality is not covered enough and more or less conducted by a single experiment. The target were monoamines - the main brain chemicals, including serotonin, norepinephrine and dopamine, that are connected with regulation of fundamental functions such as mood, creativity and motor control like we already saw with previous genes. They are also the main target for many antidepressants drugs and narcotics which in turn can cause addict to experience transcendence or experience beyond normal and even physical level of existence. In similar but much benevolent fashion a variation in a gene known as VMAT2, in that single study, was identified to be responsible for all test subjects who experienced self-transcendence compared to others that didn't have that particular variant. Whether or not this is enough to call this gene a 'god gene' is debatable but it does prove that brain chemicals encoded by specific genes can in fact affect spiritual realm with people. In addition to external chemicals that might induce spiritual thinking and religions experience we also should not exclude parasitic influence such as Toxoplasma gondii which I already mentioned in post Who's Behind the Wheel?


Refs:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2262126/
https://www.newscientist.com/article/dn7147-genes-contribute-to-religious-inclination/
https://en.wikipedia.org/wiki/God_gene
http://www.qcc.cuny.edu/socialSciences/ppecorino/.../Genetic-Basis-for-Religion.htm

Love gene
OXT
Hypothalamus activity includes production of hormone oxytocin encoded by OXT gene. The 'love hormone', how it was named after its features and properties, is also linked to social behavior. Activity of the OXT gene and production of the hormone can vary from people to people and those with low activity struggle more to identify emotional expressions of others including people in their relationships and family members. Perhaps more than with other genes, OXT is tested in correlation to the process called DNA methylation, in which methyl groups are added to DNA segments without changing their sequence. In life this can be triggered by environmental influences and bad lifestyle factors such as smoking or diet. In turn when methylation increases on the OXT gene, less oxytocin is produced and this impacts social behavior to the worse. Like with anything else and especially with genetics, balance could be the key word and further research could lead to potential treatments that could effectively fix social disorders.


Refs:
https://www.voanews.com/a/mht-love-hormone-gene...oxt-oxytocin/3387692.html
https://www.techtimes.com/articles/...people-form-healthy-lasting-relationships-study.htm
https://en.wikipedia.org/wiki/Oxytocin

Mad Scientist gene
DARPP-32
The coolest name for the gene goes to... DARPP-32, a variation within a gene that, not surprisingly is also capable to affects levels of dopamine hormone, this time in the area that influences feelings of anger and aggression. The twist with this gene is in the fact that a particular variant is also associated with increased performance in a number of cognitive tests, including IQ and memory. Actually, three out of four people inherit a version of the DARPP-32 gene, which by improving information processing in the prefrontal cortex of the brain in simple words allows and improves the brain's ability to think. These two effects combined will not give us mad scientist per se, but it does explain strange behavior and fears of some people with high IQ from the past. I am not saying that Tesla's strange fear of shaking hands or Einstein hatred for socks is granted by this gene but I am sure the genetics lottery in one way or another is the one to blame in high percentage.


Refs:
https://www.bionews.org.uk/page_91056
https://www.elitedaily.com/life/culture/genius-little-crazy/995625
https://www.medicaldaily.com/.../mad-scientist-stereotype
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1784004/

Smoking and drinking genes
CHRNA5, OPRM1
There are several genes associated with smoking, nicotine dependence, and lung cancer but among them the variant of CHRNA5 is the most prominent candidate. The process is identified as nicotine-stimulated dopamine release in the striatum (a cluster of neurons in the subcortical basal ganglia of the forebrain), a region vital to the development of substance dependence but also reward learning center. Combined, people with this particular variant are more likely to overcome casual and environmental intake of nicotine and become heavy addicted to smoking. Similarly, OPRM1 gene has been associated with subjective response to alcohol with heavy drinkers. The 'G variant' of this gene may lead to a greater susceptibility not only to addiction to alcohol but also to a variations in pain sensitivity and addiction to opioid substances.


Refs:
https://www.sciencedirect.com/topics/neuroscience/chrna5
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4000030/
https://www.ncbi.nlm.nih.gov/pubmed/23240711
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5152594/
https://drbrucekehr.com/oprm1-gene-test-addiction-genetic-testing/

In conclusion, let's get back to the beginning - the genetics and especially study of human behavior is merely at the beginning of understanding all the processes that governs our brain on the smallest levels within organic chemistry. However, we don't need any science to attribute human behavior with strange ability to give nicknames to everything and anything. Genes are no exceptions and hopefully you have identified some of them shaping what you are and how you behave. I know I have.

Image refs:
https://www.eturbonews.com/238528/non-stop-travel-destinations-for-the-adventurous/
http://knrunity.com/post/general/2016/post-787.php
https://www.askmen.com/sports/bodybuilding/warrior-based-training.html
https://blog.lifeway.com/explorethebible/blog/why-young-adults-need-bible-skills/
https://www.thebump.com/a/ways-for-dad-to-bond-with-baby
https://www.inverse.com/article/7576-best-mad-scientists
https://coach.nine.com.au/latest/red-wine-and-smoking/

Refs:
https://www.psychologytoday.com/us/blog/.../what-behaviors-do-we-inherit-genes
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3052688/
https://www.khanacademy.org/science/ap-biology/heredity/environmental-effects-on-phenotype/a/genes-environment-and-behavior
https://en.wikipedia.org/wiki/Twin_study