Your parents and family history play a major role in determining physical features, from the color of your hair to your height. But did you know that genetics also influence personality traits? To create a list of traits that have some of their origins in genetics, we collected information from scientific journals such as Nature Genetics and the Proceedings of the National Academy of Sciences (PNAS), the world’s most-cited multidisciplinary scientific serial.
Thanks to advancements in science, we now know more about the genetic components of inheritable medical conditions such as hemophilia (a blood clotting disorder), and Huntington’s disease (a degenerative nerve condition). According to a study published in Nature Genetics, personality traits such as extraversion, creativity, and compassion may also correlate to specific genetic variants.
Genetics research is evolving, and researchers are hopeful we’ll soon discover more about the impact of genetics and the environment on psychological traits. DNA test kits provide an easy way to access clues about our identities and contribute to worldwide genetic databases.
Here are 9 physical and psychological traits and conditions that researchers linked to genetics:
1. Facial expressions
A 2006 study conducted in Israel found that facial expressions associated with concentration, sadness, and anger can be inherited. Researchers videotaped 21 people born blind and 30 of their sighted relatives. Participants were asked to solve challenging puzzles, listen to a disgusting story, recount a sad or joyful personal experience, and respond to a silly question.
The blind participants had very similar facial expressions to their sighted relatives when concentrating, or experiencing anger and sadness. Moreover, a computer program able to recognize similar facial expressions correctly matched blind participants with their relatives 80% of the time.
2. Deviated septum
The septum is the bone and cartilage that divides your nasal cavity into two nostrils. The septum can become deviated or crooked, making it more difficult to breathe. A deviated septum is most commonly the result of blunt trauma, such as a blow to the face.
However, it’s also associated with conditions that affect connective tissue, such as Marfan syndrome and Ehlers-Danlos syndrome, both of which are genetic.
A study conducted by the Sleep Foundation revealed that insomnia can be genetic. According to their research, your heritability gives you an up to 58% chance of struggling with many aspects of sleep. These include how many hours of sleep you need, obstructive sleep apnea and your circadian rhythms.
4. Widow’s peak
A V-shaped frontal hairline, often called a widow’s peak, is a morphogenetic trait inherited by people from their parents. It has also been associated with a number of inherited genetic conditions, such as Aarskog-Scott Syndrome and Opitz Syndrome.
Certain studies also show that there’s a link between a widow’s peak and craniofacial clefts, or malformations of part of the face. However, the association between a widow’s peak and the severity of these conditions has not yet been defined.
5. Caffeine response
Every person responds differently to caffeine. While some experience a sense of alertness and intense focus, others find that is makes them jittery and can even bring on anxiety. An increasing amount of scientific evidence, as published by the National Library of Medicine, shows that these responses may be genetic.
Genetic factors may directly influence individual responses by changing the acute or chronic reactions to caffeine. They could also play an indirect role by altering the psychological or physiological processes related to the effects of caffeine.
6. Sensitivity to bitter food
About a quarter of the population has a taste receptor gene called TAS2R38, which can make foods such as leafy greens and hoppy beers taste bitter. The perceived bitterness of these varies among individuals and depends on how strongly food compounds bind to the receptor.
In a 2014 study of 93 Caucasian participants, TAS2R38 was associated with a bitter taste on the papillae of the tongue when it was swabbed with ethyl alcohol. The researchers concluded that variations in the TAS2Rs gene may explain why alcoholic beverages taste bitter to some people, but not to others.
7. Sneezing in the sun
Autosomal Dominant Compelling Helioopthalmic Outburst syndrome, or ACHOO syndrome, is characterized by a person sneezing after suddenly being exposed to bright light, usually strong sunlight.
The cause of ACHOO syndrome is not well understood. However, researchers do know it is inherited as an autosomal dominant trait. That means if one parent is affected, a child has a 50% chance of inheriting ACHOO syndrome.
The oxytocin receptor gene (also known as the OXTR gene) codes for the receptor of the same name, causing this hormone to bind and affects the whole body. Studies have linked part of the OXTR gene to psychological traits including optimism.
The findings of a 2011 study suggest that people with a certain variation of the OXTR gene inherited from both parents, are more optimistic than those who inherited the variation from only one parent or not at all.
9. Life satisfaction
A study of twins published in 2012 by an international team of researchers found that genes can explain about 33% of the variations reported in life satisfaction. Although at first, the researchers found greater life satisfaction among people with a certain variant of the 5-HTT serotonin transporter gene, they had difficulty recreating their results in an independent sample.
The findings suggest that more work is needed to better understand the relationship between the 5-HTT gene variant and life satisfaction.
Can Your Genetics Map Out Your Life
While genetic testing can predict a lot of the traits you’re likely to inherit, it is almost never 100% on the money. Your genes are simply markers that influence your medical future, looks and personality. But these are also influences by external factors, such as where you reside, what you eat and drink, the type of job you do and much more.
So trust in your genes to give a glimpse into what your future may be, but don’t rely on them entirely. They may not always be accurate.