You probably already know that your parents and family history play a major role in determining your physical features, from the color of your hair to your height. But did you know that genetics also influence your 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 the field of science, we now know more about the genetic component 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, more is being uncovered about how traits such as extraversion, creativity, and compassion may also have correlations to specific genetic variants.
Genetics research is an evolving field, and researchers are hopeful we’ll soon discover more on how psychological traits are impacted by genetics as well as environmental factors. That being said, DNA test kits provide an easy way to access clues about our identities and contribute to worldwide genetic databases.
Here are 10 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.
Those who were blind had very similar facial expressions to their sighted relatives when concentrating, feeling angry, or feeling sad. 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 is also associated with conditions that affect connective tissue, such as Marfan syndrome and Ehlers-Danlos syndrome, both of which are genetic.
A team led by researchers at the University of Basel in Switzerland found maternal symptoms of insomnia were associated with a child’s sleep pattern as objectively measured by in-home electroencephalography. Maternal insomnia was associated with less total sleep time, more stage 2 sleep, less slow-wave sleep, a later time to sleep onset, and a later wake time for their child.
The insomnia symptoms of both parents influenced parents’ perceptions of their children’s sleep habits. As demonstrated in research on parental insomnia, parents with insomnia report more problems with their children’s sleep such as, refusal to adhere to a designated bedtime, duration of sleep, incidents of waking up during the night, and/or daytime sleepiness.
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.
Studies also exist of 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. There is an increasing amount of scientific evidence, as published on the National Library of Medicine, that these responses may be genetic. Genetic factors may directly influence individual responses by changing acute or chronic reactions to caffeine.
These factors may also play an indirect role by altering the psychological or physiological processes related to the effects of caffeine, such as sensitivity to anxiety and the generally reinforcing effects of substance use. Genes can also affect the body’s response to long-term caffeine use.
6. Sensitivity to bitter food
About one quarter of the population has a taste receptor gene known as TAS2R38, which can make foods such as leafy greens and hoppy beers taste bitter. The perceived bitterness of these foods 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 genetic 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, known as ACHOO syndrome, is characterized by sneezing after sudden exposure 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, so 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 oxytocin receptor, to which the hormone oxytocin binds and exerts its effects throughout the body. Studies have linked part of the OXTR gene to psychological resources including optimism.
The findings of a 2011 study suggest that those who inherited a certain variation of the OXTR gene 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 variation in reported 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 replicating their results in an independent sample.
The findings suggest more work is necessary to better understand the relationship between the 5-HTT gene variant and life satisfaction.