Heredity/Inheritance Patterns: 9 Surprising Hereditary Traits
We inherit our traits from our parents (personality traits, physical traits, polygenic traits and so on), and this is driven by the genetic material that is passed down from them. More specifically, we inherit half of our DNA—the genetic material that determines mostly how we appear on the outside—from our mother and the other half from our father. Inbiological terms, our genetic makeup (our genotype), manifests itself as our external makeup, also known as phenotype. And this phenotype is a mix of our parent’s genes, half of which we receive from one side and the other half from the other side. This genetic material is then shuffled around during cell division and distributed evenly in all cells, driving all aspects of our phenotype such as hair color, eye color, height, body composition, height, and several other characteristics. However, inheritance patterns work in a very interesting manner, and not everything about us is inherited as some phenotypes are the result of the environment affecting our genes.
Still, there are some surprising hereditary traits that one would never expect to be inherited from our parents. A list of nine is elaborated below.
1. Pain Tolerance
It turns out that those among us who have inherited red hair from their parents have also inherited an ability to tolerate pain a lot better. According to a study that was conducted at Aalborg University in Denmark, among subjects that were injected with capsaicin, a substance that puts the heat in chili, those who had red hair were able to tolerate this type of pain a lot more. This is also the reason why they are able to tolerate spicy food a lot more (as well as a pinprick). However, there is additional research that points to the fact that redheads are a lot less sensitive to anesthesia and a lot more sensitive to cold temperatures.
2. Sneezing at the Sun
The act of sneezing at the sun is called the Autosomal Dominant Compelling Heliopathic Outburst (ACHOO Syndrome). Those who have the syndrome react to exposure to bright lights by sneezing. This trait is dominant, so if one of the two parents has it, chances are about 50% that the child will inherit the trait.
3. Metabolizing Caffeine
Believe it or not, the ability to metabolize coffee—caffeine, to be exact—is a genetic trait that is inherited. The gene that is responsible for this is PDSS2 (Prenyl (Decaprenyl) Diphosphate Synthase, Subunit 2. More specifically, those who have a stronger expression of PDSS2 drank less coffee. The hypothesis behind this is that the stronger gene expression leads to slower metabolism of coffee, which, in turn, culminates in less of a need for it. Those whose PDSS2 expression is lower will likely need a venti cup.
4. Sweaty Hands
Sweaty and balmy palms may not just be the result of your nerves. If your hands sweat excessively or even chronically, it is probably due to your genes. If so, DNA directs how your sympathetic nerve that governs your flight or fight response expands and constricts the blood vessels in your hands and feet. This condition is called hyperhidrosis, which is a fancy term for “sweaty palms syndrome.” Those who have hyperhidrosis most likely have a history of it running in their families. However, contrary to other usual dominant traits, this condition is passed on with only a 28% chance, indicating that other genes may also be at play. An estimated 5% of the population is affected by hyperhidrosis.
More than just a culprit of a stress-filled day, insomnia is one of many traits that is inherited. In fact, recent research pointed out that there may be seven genes that increase the risk of insomnia. What’s more, these genes may also be behind several anxiety disorders, depression, and neuroticism. So, from one perspective, this is a relief in a way. Knowing that it is not all in your head is comforting and knowing a bit more about the disease is a first step toward finding a cure for it one day.
6. Aggression during Toddler Years
The “terrible twos” did not get its name for no reason. This developmental stage in a toddler’s life is filled with emotional ups and downs. However, if this period is a bit more intense than usual, it may be due to a genetic reason. According to a recent study, aggressive behaviors such as hitting, biting, and kicking are more due to genetics rather than the environment. However, as long as it is handled appropriately, this behavior does not usually carry on into adulthood.
7. The Ability to Trust
Whether or not you believe the things people tell you may not only be the result of your environment, it could also be in your genes. According to researchers at the University of Arizona, trust is 30% heritable. However, your natural inclination to be suspicious as well as distrusting may be largely due to the number of negative experiences you have had in your life. In fact, distrust is largely a trait that is acquired from the social experiences you may have had.
8. Sweet Tooth
A recent study at the University of Guelph has published findings that highlight an interesting genetic trait, namely the desire to snack. Approximately 80% of preschool-aged kids had at least one of the genetic markers that lead to them wanting to snack on sweets rather than the vegetable counterparts. Furthermore, a study that looked at the TAS2R38 gene that is behind the bitter tasted of vegetables like Brussels sprouts and kale and found that those who did not taste the bitterness actually enjoyed 200 more servings of vegetables on a yearly basis. What a difference!
9. Optimism vs.Pessimism
If the glasses in your life are mostly half empty rather than half full, it may not just be a reflection of life having beaten you down. According to a recent study, the OXTR gene that codes for the oxytocin hormone may be at play. Individuals with certain markers in the gene were just less optimistic than those who did not have that marker. However, while part of this may be due to genetics, it is not the only determining factor.