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Humans share an astonishingly similar genetic makeup, especially when compared to other species. Yet, even the smallest genetic variations or environmental factors can lead to the development of traits that make us unique. These differences might show up in everyday features such as hair color, height, or facial structure, but sometimes they result in remarkable traits that set an individual or group apart from the rest of humanity.
10. Immunity to High Cholesterol
While the majority of us are advised to cut back on foods like fried items, bacon, eggs, and other foods high on the 'cholesterol-raising' list, there are a fortunate few who can indulge in all of these without a second thought. No matter their diet, these individuals have near-zero levels of 'bad cholesterol' (low-density lipoprotein), which is a major risk factor for heart disease.
These individuals were born with a genetic mutation. Specifically, they are missing functional copies of a gene called PCSK9. Although it's typically unfortunate to be born without a gene, in this case, the absence seems to have some unexpected positive effects.
About a decade ago, scientists uncovered the link between this gene (or the absence of it) and cholesterol, prompting pharmaceutical companies to race to develop a pill that could block PCSK9 in other people. The drug is on the verge of receiving FDA approval. Early trials have shown that patients who have taken the drug experienced cholesterol reductions of up to 75 percent.
To date, scientists have only identified the mutation in a small number of African Americans, who also enjoy the advantage of a 90-percent decreased risk of heart disease.
9. Resistance to HIV
The human race faces a variety of existential threats—ranging from asteroid impacts to nuclear war, and even extreme climate shifts. Yet, one of the most terrifying dangers may be a highly contagious and deadly virus. In the event of a pandemic, survival would likely depend on the few who possess immunity to the disease. Thankfully, there are certain individuals who have natural resistance to specific diseases.
Consider HIV as an example. Some individuals carry a genetic mutation that disables the CCR5 protein, which HIV typically uses to invade human cells. Without this protein, the virus is unable to enter cells, making these individuals highly resistant to infection.
However, experts note that while these individuals are resistant to HIV, they are not completely immune. There have been cases where individuals with the CCR5 mutation have contracted HIV and even succumbed to AIDS. This is due to the fact that some rare forms of HIV have adapted and found alternative proteins to use for cellular invasion, highlighting the adaptability of viruses.
Those with two copies of the defective CCR5 gene have the highest resistance to HIV. Currently, this genetic trait is found in about 1 percent of Caucasians and is far less common in other ethnic groups.
8. Resistance to Malaria
Those with particularly high malaria resistance often carry the gene for sickle cell anemia, a potentially lethal condition. While no one would wish for the ability to ward off malaria only to suffer from deformed blood cells, there is one scenario where the sickle cell gene proves advantageous. To fully grasp this, it’s important to understand the basics of both malaria and sickle cell anemia.
Malaria is a parasitic disease transmitted by mosquitoes, claiming the lives of approximately 660,000 people each year, or leaving others in a near-death state. The parasite targets red blood cells, multiplying within them. After a few days, the parasite bursts out, destroying the blood cell and spreading to others. This cycle repeats until treatment, the body's immune system, or death intervenes. The cycle results in blood loss, weakens vital organs such as the liver and lungs, and increases the likelihood of blood clots, which may trigger seizures or a coma.
Sickle cell anemia alters the shape and structure of red blood cells, impairing their ability to circulate oxygen throughout the body. However, these mutated cells also pose a challenge for malaria parasites, making it difficult for them to attach and infect the blood cells. As a result, those with sickle-shaped blood cells are naturally resistant to malaria.
You can benefit from malaria resistance without actually having sickle cells by simply being a carrier of the sickle cell gene. To develop full-blown sickle cell anemia, an individual must inherit two copies of the mutated gene, one from each parent. However, if only one mutated gene is inherited, the person will possess enough abnormal hemoglobin to resist malaria but will not develop the disease itself.
Due to its strong resistance to malaria, the sickle cell trait has become highly prevalent in regions where malaria is common, with up to 10–40 percent of individuals in these areas carrying the genetic mutation.
7. Cold Tolerance
Inuit populations, along with other groups living in extreme cold climates, have adapted to survive in these harsh environments. But do these individuals merely learn survival strategies, or is there a deeper biological difference that sets them apart?
People living in cold environments exhibit different physiological responses to low temperatures compared to those from more temperate regions. It seems there may be a genetic factor at play in these adaptations, as even if someone moves to a cold climate and spends decades there, their bodies will never fully adapt to the same extent as those born and raised in these conditions. For example, studies have shown that indigenous Siberians are better equipped to handle the cold than non-indigenous Russians in the same area.
Those native to colder climates generally have higher basal metabolic rates, roughly 50 percent higher than those from temperate zones. These individuals can also maintain their body heat more effectively without shivering and have fewer sweat glands across their bodies, with more concentrated around their faces. In a study comparing skin temperatures across different races in response to cold, Inuits maintained the highest skin temperature, followed by other Native Americans.
Such physiological adaptations help explain why Aboriginal Australians can sleep on the cold ground without shelter or clothing, enduring no negative effects, and why Inuits can live in subzero temperatures for much of their lives.
The human body is far better suited for heat adaptation than for cold, making it remarkable that some populations not only survive but thrive in freezing environments.
6. Adaptations for High Altitude
There’s no question that Tibetans and Nepalese possess remarkable physical strength at high altitudes, but what exactly gives them the ability to work tirelessly in oxygen-thin environments, while others struggle just to survive?
Living at altitudes exceeding 4,000 meters (13,000 ft), Tibetans are accustomed to air that holds roughly 40 percent less oxygen than at sea level. Over generations, their bodies adapted by developing larger chest sizes and enhanced lung capacities, enabling them to take in more air with each breath.
Unlike people from lower altitudes who increase red blood cell production in low-oxygen environments, high-altitude populations, like Tibetans, evolved to produce fewer red blood cells. While an increase might temporarily boost oxygen delivery, it thickens the blood over time, posing a risk of clots and other severe complications.
Sherpas have a unique advantage in that their brains benefit from better blood circulation, and they are generally less vulnerable to altitude sickness, a crucial factor in their ability to withstand the high-altitude challenges of Everest.
Even when residing at lower altitudes, Tibetans continue to exhibit these characteristics, and studies have shown that many of these traits aren’t just temporary phenotypic changes that would disappear at lower elevations, but rather genetic adaptations. A notable genetic alteration took place in a segment of DNA known as EPAS1, which encodes a protein that regulates the body's response to oxygen. This protein helps manage red blood cell production and explains why Tibetans don’t overproduce red blood cells in low-oxygen conditions, unlike most other people.
The Han Chinese, who are the lowland relatives of the Tibetans, do not share these genetic traits. These two groups diverged around 3,000 years ago, meaning these genetic adaptations emerged within roughly 100 generations—an incredibly short period in evolutionary terms.
5. Immunity to a Brain Disease
If we needed any more reasons to steer clear of cannibalism, consuming human flesh is far from a healthy choice. In the mid-20th century, the Fore people of Papua New Guinea gave us a grim example when their tribe faced a devastating epidemic of Kuru—a fatal and degenerative brain disease transmitted through the practice of eating human flesh.
Kuru is a prion disease closely related to Creutzfeldt-Jakob Disease (CJD) in humans and bovine spongiform encephalopathy (BSE), also known as mad cow disease. Like all prion diseases, kuru destroys the brain, creating sponge-like holes. The symptoms include a gradual loss of memory and intellect, changes in personality, and seizures. Though prion diseases can persist for years, kuru typically causes death within a year of symptom onset. It’s important to note that while very rare, a prion disease can be inherited, but it is most often transmitted through the consumption of infected individuals or animals.
At first, anthropologists and medical professionals were puzzled as to why kuru was spreading among the Fore tribe. In the late 1950s, it was finally discovered that the infection was being passed on during mortuary feasts, where tribe members would honor their deceased relatives by eating them. Primarily, women and young children took part in this cannibalistic tradition, which led them to be the most affected. Before the practice was outlawed, some Fore villages had almost no young women left.
However, not everyone who was exposed to kuru succumbed to the disease. Survivors carried a unique variation of a gene called G127V, which provided them with immunity to the brain disorder. This genetic trait is now widespread among the Fore and neighboring communities, which is remarkable considering kuru only emerged in the region around 1900. This serves as one of the most significant and recent examples of natural selection at work in humans.
4. Golden Blood
Although type O blood is often considered the universal donor, allowing anyone to receive it, the truth is more complex. The blood system itself is far more intricate than many people realize.
While the majority of us know about the eight basic blood types (A, AB, B, and O—each of which can be positive or negative), there are actually 35 known blood group systems, each containing millions of variations. Blood types that don’t fit into the ABO system are deemed rare, and individuals with these types may struggle to find a compatible donor in emergencies.
However, there’s rare blood, and then there’s truly extraordinary blood. The rarest known type is called “Rh-null,” which, as its name suggests, has no Rh system antigens. While it’s not uncommon for a person to lack one or more Rh antigens (e.g., people who lack the Rh D antigen have “negative” blood), it is exceedingly rare to find someone without any Rh antigens. So rare, in fact, that only about 40 people globally are known to have Rh-null blood.
What makes Rh-null even more fascinating is its superiority over type O blood as a universal donor. While O-negative blood isn’t always compatible with other rare negative blood types, Rh-null can be safely transfused into almost anyone. This is because our immune system typically rejects blood that contains antigens we don’t have, but since Rh-null lacks all Rh, A, and B antigens, it can be given to almost anyone.
Unfortunately, there are just nine known Rh-null donors in the world, making it available only in critical situations. Due to its extreme rarity and immense value as a potential life-saving resource, some doctors have even sought out anonymous donors (a practice that is typically prohibited) to acquire a sample.
For those with Rh-null blood, life is a bittersweet balance. While they carry a gift that can save the lives of others with rare blood types, their own chances of receiving a compatible transfusion are limited to just nine known donors.
3. Require Minimal Sleep
Have you ever felt like some people manage to get more done in a day than you do? Well, it might be true—at least when it comes to their waking hours. Certain individuals can function on just six or fewer hours of sleep each night. Rather than struggling through the day, they thrive with far less rest than most of us, who still feel groggy after a full eight hours.
These exceptional individuals aren’t necessarily tougher or more disciplined than the rest of us. They haven’t trained themselves to get by on less sleep. Instead, they possess a rare genetic mutation in the DEC2 gene, which enables them to function on far less sleep than the typical person requires.
If regular sleepers were to reduce their slumber to six hours or less, they’d soon face negative consequences. Chronic sleep deprivation can trigger serious health issues, such as high blood pressure and heart disease. However, individuals with the DEC2 mutation don't suffer from these common side effects of insufficient sleep. Despite their shorter sleep duration, they avoid the typical health risks. Researchers believe this gene allows them to sleep more efficiently, entering deeper REM stages, which ultimately reduces the overall need for sleep.
This genetic mutation is extremely rare, affecting less than 1 percent of those who claim to be short sleepers. So, even if you think you might have it, the odds are you probably don’t.
2. Exceptionally Dense Bones
Aging often brings a slew of physical issues, one of the most common being osteoporosis—where bones lose mass and density. This results in fractures, broken hips, and stooped spines, which no one wishes to face. However, not all is lost, as a select group of people carry a unique gene that could potentially hold the key to preventing or even curing osteoporosis.
The gene is present in the Afrikaner community (South Africans with Dutch ancestry), and it causes individuals to gain bone mass throughout their lifetime instead of experiencing bone loss. This mutation occurs in the SOST gene, which regulates a protein (sclerostin) that controls bone growth.
When an Afrikaner inherits two copies of the mutated gene, they develop sclerosteosis, a disorder that causes excessive bone growth, gigantism, facial deformities, hearing loss, and premature death. Clearly, this condition is much more severe than osteoporosis. However, inheriting only one copy of the gene does not lead to sclerosteosis, and individuals simply have exceptionally dense bones throughout their life.
Currently, only heterozygous carriers of the gene benefit from its effects, but researchers are examining the DNA of Afrikaners in hopes of discovering ways to reverse osteoporosis and other bone-related disorders in the wider population. Their findings so far have led to the initiation of clinical trials for a sclerostin inhibitor that can stimulate bone growth.
1. Crystal-Clear Underwater Vision
The majority of animals' eyes are built for either underwater or aerial vision, but not both. Human eyes, for example, are perfectly suited for seeing in the air. When we attempt to open our eyes underwater, the world appears blurry. This happens because water and the fluids in our eyes have similar densities, reducing the amount of refracted light that can enter. Less light refraction leads to blurred vision.
This information makes it even more fascinating that a group of people called the Moken can see clearly underwater, even at depths as deep as 22 meters (75 feet).
The Moken spend the majority of the year living on boats or stilt houses, returning to land only when they need basic supplies, which they trade for food or shells harvested from the ocean. They rely on traditional methods to gather resources, using neither modern fishing gear, diving masks, nor poles. The children of the Moken are tasked with collecting food like clams or sea cucumbers from the ocean floor. Over time, due to the repetitive nature of this task, their eyes have developed the ability to change shape when submerged to enhance light refraction. This allows them to easily tell the difference between edible clams and ordinary rocks, even when they're many meters underwater.
When tested, Moken children were found to have underwater vision that was twice as sharp as that of European children. However, it appears this ability could be a skill we all could develop if our environment required it. Researchers have successfully trained European children to complete underwater tasks with similar efficiency to the Moken.
