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In high school biology, we’re taught about recessive and dominant genes—often alongside more than we care to know about pea plants and moths. Yet these lessons only touch the surface of what genetics can teach us about the human body. Recent breakthroughs in human genetics have uncovered surprising insights about our past and present that encourage us to rethink our place in the world.
10. The Genghis Khan Legacy
A significant number of people alive today can trace their ancestry back to Genghis Khan, according to a well-supported theory. As a conqueror, his armies devastated vast areas of Asia, but he was also said to have been equally prolific in his personal conquests.
There’s a minor issue, though. When a Florida accountant received the results of a DNA test indicating he was a descendant of Genghis Khan, further examination revealed that these tests actually detect genetic markers common in specific regions of Eurasia—territories once ruled by Khan. This doesn’t guarantee Mongol royal blood in the Floridian’s veins; it only suggests it's a likely possibility. Since Genghis Khan’s tomb remains undiscovered, we don’t possess an authentic sample of his DNA.
The idea of Genghis Khan’s extensive lineage traces back to a 2003 study, which estimated that around 16 million men alive today could be his descendants. In 2015, geneticists revisited the research and uncovered something astonishing. The Mongol markers in our DNA weren't the only ones, revealing that at least 10 other men in history had similarly expansive family trees like Khan’s.
A 16th-century ruler from the Qing Dynasty, Giocangga, is said to have around 1.5 million descendants in China today and is typically recognized as one of these influential men. Another such figure was from Ireland, a member of the Ui Neill family who began spreading his genetic legacy during the medieval period. While the identities of the remaining individuals remain unknown, we can pinpoint their general origin and era. Some of these founding fathers are dated between 2100 and 300 BC and were located across the Middle East, India, and parts of Southeast and Central Asia. The European Journal of Human Genetics concludes that one thing is certain—the mystery men were most certainly part of powerful political, military, or economic dynasties, whose social status provided them ample opportunities to extend their influence.
9. Genetics and Alcohol
If you're one of the unlucky ones who experiences a severe hangover after just a drink or two, your ancestors may be partly responsible. A series of recent studies examined how much our genetics play a role in how we react to alcohol, revealing that roughly 55 percent of our hangover experiences the morning after a night out are influenced by our genetics. The rest can be attributed to factors like how much and what kind of alcohol we consumed.
The first wave of data came from a 1972 study, which involved 13,511 male twins, all World War II veterans, who were questioned about their hangover experiences. Later, both male and female twins were asked about how they felt after a night of drinking. Despite the change in gender, the results were largely consistent. The research also indicated a genetic connection to both hangover resistance and susceptibility—43 percent of participants reported that they could drink without suffering a hangover the next day.
A 2010 study from the University of North Carolina uncovered something even more fascinating—a gene that could help certain people avoid the dark, dismal path of alcoholism. The study identified a gene dubbed the “tipsy” gene, and found that between 10 and 20 percent of participants carried a variant of the gene that made them more sensitive to alcohol. The gene, CYP2EI, helps the body break down alcohol in the brain as well as the liver. Some individuals with a specific version of the gene processed more alcohol in the brain, feeling its effects more quickly and intensely than others without the gene. The study, conducted on students with at least one parent who was alcohol-dependent, suggested that both genetic and environmental factors contribute to the hereditary nature of alcoholism.
8. Russia's Tame Foxes
Much of what we know about Russian geneticist Dmitry Konstantinovich Belyaev comes from the student who continues his research today, still breeding foxes in Russia and seeking the secrets to domestication.
When it comes to dangerous occupations, “geneticist” probably isn’t on anyone's radar. But in the early 20th-century Soviet Union, it was considered forbidden. Belyaev followed the path of his older brother, Nikolai, who was arrested by the secret police in 1937 and executed for his genetic work. After serving in World War II, Belyaev began searching for the genetic key that turned wild dogs into domesticated pets. He sought to recreate domestication with silver foxes, partly because he could disguise his experiments under the cover of the fur trade.
In the isolated regions of Siberia, he set out to tame his foxes. Starting with 30 males and 100 females, Belyaev initiated a selective breeding process, focusing on behavior rather than traits like coat color and quality, which fur farms typically valued. Foxes that showed aggression, such as biting, were excluded from breeding, while those that weren’t afraid of him were paired together.
After 45 generations, Belyaev successfully bred a group of foxes that interacted with humans much like domesticated dogs. The domestication process also had unexpected effects on the foxes' appearance. Their fur became irregular in color, and their skin pigmentation changed. In essence, they were becoming cuter. As a commercial venture, the foxes were worthless, but Belyaev’s disguise as a fur farmer was so convincing that his colleagues in the business would joke about how useless the animals' pelts were and how he had inadvertently turned them into pets instead.
Belyaev passed away in 1985, but his experiments carried on through his protege, who continues to selectively breed foxes. These foxes now have curly tails, floppy ears, and behave like dogs, enjoying human interaction. However, there remains one final challenge before the experiment can be deemed a success: the foxes need to be trained like dogs. Further research is required to explore the connection between the domestication gene and the physical traits associated with it, such as floppy ears and spotted fur. Currently, the project is struggling due to a lack of funds and volunteers, and the latest generations of foxes languish in their cages.
7. The Genetic Mutations of High-Altitude Inhabitants
At high altitudes with thinner air, most people experience problems. With lower oxygen levels in the blood, they often feel fatigued, suffer from headaches, and, in extreme cases, become more prone to heart attacks and strokes. Some residents of these high-altitude regions develop chronic mountain sickness (CMS), also referred to as Monge’s disease.
While studying potential treatments for CMS, researchers investigated the differences between those who experience CMS and those who don’t. With over 140 million people living at elevations where serious physical challenges are common, there was no shortage of subjects to study.
Many of the CMS sufferers reside in the Andes of South America. On the other hand, high-altitude inhabitants in Ethiopia rarely suffer from CMS, and it only occasionally affects the mountain dwellers of Tibet. These three groups were selected for the study not only because of their diverse reactions to living at high altitudes, but also because many of them have lived in these regions for countless generations—enough time to offer insight into how living at high altitudes has shaped their genes through evolution and adaptation.
The researchers discovered that people who have adapted to life at high altitudes possess certain genetic mutations that help them manage the low oxygen levels. Two genes, SENP1 and ANP32D, were more prominently expressed in individuals suffering from chronic CMS. Those who did not have CMS carried different versions of these genes. By linking these genes to their expression in the body and understanding how this affects oxygen usage, this research could provide vital medical breakthroughs.
6. Body Image Beliefs
It’s well-known that our genes determine traits like the color of our eyes and hair, our height, and our body type. But how much do our genes influence how we feel about these physical features?
While societal pressures from media, television, and magazines shape the ideal body type for both men and women, it turns out that the desire for a thin or muscular physique has much deeper roots than just these external influences. Researchers at Michigan State University examined fraternal and identical twins and asked them about their perceptions of beauty standards. The study, using twins because they share similar environments, revealed that identical twins were far more likely to have similar views that a slim body is the standard of beauty.
The closer the genetic similarity, the more alike their responses. Fraternal twins, even though raised in the same environment, didn’t share the same strong “thin-ideal internalization” as identical twins, suggesting that our genetics might hold a key to our perception of body image. The study was based on the idea that some individuals are more vulnerable to negative body image than others, which leads them to react differently to media that promotes beauty standards that are unrealistic, unattainable, and unhealthy for the majority of the global population. Research continues on this topic.
5. Genetic Adam And Eve
In the Bible, the origins of humanity are attributed to Adam and Eve. Interestingly, geneticists seem to agree with this idea. Well, sort of.
The individuals identified by geneticists as the 'Adam' and 'Eve' of humanity are the two people whose DNA has persisted through the ages. In 1987, geneticists began studying DNA from a variety of people and created what they called a 'molecular clock,' which helped trace the evolution of human DNA. From this, they determined that all the people studied shared a common ancestor. This 'Eve' is thought to have lived in Africa around 200,000 years ago and her mitochondrial DNA has survived in modern humans.
There is also a male counterpart, a single ancestor whose Y chromosome is passed from father to son. Since the Y chromosome is only inherited through the male line, many versions of it have disappeared over generations, but the Y chromosome of a single ancestor has survived through the generations, marking geneticists' 'Adam.'
Initially, early efforts to trace the lineage of Adam suggested that he lived around 100,000 years ago, generations after Eve. However, further studies have extended Adam’s existence to somewhere between 120,000 and 156,000 years ago, while a closer examination of mitochondrial DNA from male subjects indicated that Eve may have lived between 99,000 and 148,000 years ago.
Most of the current research indicates that the Y chromosome we have today traces back to a completely different species, an ancient ancestor of Homo sapiens. Even more intriguingly, the University of Arizona has uncovered a family whose Y chromosomes seem to be unrelated to the Adam whose genes are present in everyone else.
Unsurprisingly, this discovery has been embraced by many Christians as scientific validation of the Bible’s literal accuracy. From one perspective, the scientific evidence supporting the possibility that the two parents whose DNA is carried by all humans lived at the same time provides some Christians with tangible proof of God’s creation of the human race from one man and one woman.
4. The Discovery Of A ‘Gay Gene’
A common argument from those opposing the LGBT community is that being gay is a choice. Geneticist Dean Hamer, however, believes there’s a biological marker for homosexuality. This marker is inherited through the maternal line and is located on a section of DNA called Xq28.
Hamer’s study combined interviews with genetic research. He examined pairs of gay brothers and their family members, ultimately discovering that the gay brothers shared a specific genetic marker on the Xq28 section of their DNA. Unfortunately, follow-up research has been limited. In contrast, after Hamer’s similar study linking a gene to anxiety, over 400 follow-up studies were conducted.
There has been little interest in further investigating the gay gene, except for a few researchers who dismissed Hamer’s findings. One of the few other studies was conducted at Rice University, with one researcher making it clear from the outset that he didn’t believe in the existence of such a gene.
Hamer does have his supporters, though. Several additional studies have been conducted, including one that looked at children who were born male but surgically altered to female as babies. Despite the subjects believing they had been born female, most were still attracted to women, suggesting that sexual preference development involves more than just environmental factors.
The implications of Hamer’s discovery and the potential identification of a gay gene could have significant consequences. As recently as 2007, CNN reported that most Americans still believed being gay was a choice. Identifying a gay gene could help shift this perception.
Genetic research has already established clear links between certain physical traits and being gay. If one identical twin is gay, the likelihood of the other twin also being gay is higher compared to fraternal twins. Additionally, gay men are more likely to be left-handed and have hair that grows in a counterclockwise direction.
3. The Dominance of Mothers Over Fathers
When considering who has contributed the most genetically to humanity, the answer might surprise you. Hint: It’s not men.
A study by the Max Planck Institute for Evolutionary Anthropology revealed an unexpected finding: despite the common stereotype of men being prolific in reproduction, there have actually been more mothers than fathers throughout history. This can largely be attributed to polygyny, the practice where one man has multiple wives or partners.
The research examined genetic data from individuals worldwide, focusing on mitochondrial DNA and the Y chromosome. The results provided such a clear picture that geneticists were able to map reproductive patterns across different regions. In East Asia and Europe, significant differences in male-inherited genetic material suggested that women were more likely to leave their birthplaces, settle elsewhere, and raise their families far from home. In contrast, in Africa and the Americas, the opposite was found.
Further investigations revealed surprising insights that challenge our conventional understanding of world history. Genetic tracking of early Americans suggests that more women than men likely migrated to the New World. Additionally, studies uncovered a population bottleneck in Africa, where some groups moved out, settling in new lands with as few as 25 women and 15 men. The idea that women played a pivotal role in migration and contributed significantly to human genetic diversity contradicts the usual narrative.
2. Our Genetic Influence on Marital Relationships
While it's easy to see how our genes affect our physical characteristics, it's even more astonishing to learn that certain genes have been linked directly to our happiness in marriage and, for some, our capacity for monogamy.
In 2008, geneticists revisited a 2005 study on the monogamous prairie vole and applied its findings to human relationships. It was discovered that the voles possessed a particular allele—allele 334—which regulated a brain chemical responsible for emotional control. Researchers found that when examining men who carried this allele, they could predict their relationship outcomes. Men with the allele were more prone to marital issues or avoiding marriage altogether. If a man inherited two copies of this allele, his chances of facing relationship or marital difficulties significantly increased.
Another gene, 5-HTTLPR, has been identified as influencing marital happiness. This gene exists in different forms, and those with one or two long versions of it tend to be more content in their relationships. Conversely, individuals with two short alleles often experience more tumultuous relationships. While these findings don't suggest that people with this genetic configuration are unsuited for marriage, they do feel the highs and lows of relationships more intensely.
Genetic studies have also linked certain traits to divorce. Research on both fraternal and identical twins suggests that our genetic makeup may predispose us to either maintain a stable marriage, divorce, or even remarry after a divorce.
It has also been discovered that people tend to choose spouses with not just similar personalities but also similar genetic traits. A study involving 1,716 married couples revealed that couples were genetically more similar to each other than to randomly paired individuals from the same study. This phenomenon is known as 'genetic associative mating.' While this might seem to contradict the idea that opposites attract or the need to diversify the gene pool, it's believed that certain genetic traits are better off matching for successful reproduction, while most others can align without any negative consequences.
1. The Genetic Death Of The Paleo-Eskimos
Studying the archaeological remains of the first people to cross the Bering Strait land bridge from Siberia to North America has historically been challenging due to the extreme climate and the remote locations once inhabited by these ancient tribes. Later research divided these early settlers into two groups—the Paleo-Eskimos and Neo-Eskimos—separated by approximately 4,000 years. However, more recent genetic research has significantly reshaped our understanding of these first inhabitants of the continent.
The early Paleo-Eskimos survived by hunting reindeer and musk ox, while later Paleo-Eskimo cultures adapted to the sea, hunting small whales and seals. The Neo-Eskimos, who crossed the Bering Strait much later, were better equipped with advanced weapons, tools, and transportation methods. Their ability to hunt larger whales and use dog sleds for mobility allowed them to thrive and expand.
Recent genetic evidence has uncovered that the Paleo-Eskimos and Neo-Eskimos did not interact much, if at all. The DNA of Neo-Eskimos can still be found in contemporary populations, but the genetic traces of the Paleo-Eskimos have disappeared from the genetic record. Eske Willerslev, a geneticist at the University of Copenhagen’s National Museum of Natural History, highlights the significance of this discovery: 'In other studies, when we observe people meeting, they might fight, but they often also interbreed. However, this doesn’t seem to have happened with these groups.'
Although the Paleo-Eskimos, as described by Willerslev, have no direct descendants today, geneticists have still identified traces of ancient DNA in present-day populations. Jody Hey, a geneticist at Rutgers University, conducted a study that uncovered DNA from 70 individuals who may have crossed the Bering Strait 12,000 to 14,000 years ago, predating the Paleo-Eskimos and Neo-Eskimos. According to Hey, her research 'uses actual DNA sequences from Asian peoples and Native Americans, offering a detailed view of ancient populations.'
