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Centuries ago, right smack in the middle of northeast Asia, a 16-year-old youth married his first wife. A few years later, he had decided what he was to do with his life: conquer and pillage dozens of tribes across the Asian continent, creating one of the largest empires known to humanity. So, he began to build an army. A very, very big army.
This man, this megalomaniac; we know him as Genghis Khan.
Long and brutal story short, this man had accomplished what he had set out to do; taking many wives along the way, he had established the Mongol empire. With these wives he had children. Gratuitous, unnecessary and ridiculous amounts of children. Genghis Khan had so many children that we can only estimate within a thousand-child margin of how many children he may have had. He could very well have made a baby per day for five years, but we’re not certain.
His ancient legacy now a household name in most of modern America, he’s been the focus of many a historian’s curiosity for quite some time. But, according to what these historians have uncovered, his legacy may not be all that “ancient” after all. In fact, his legacy still lives on today in the form of nearly 16,000,000 men.
Could you be the direct descendant of this ancient Mongolian warlord?
There’s a ten percent chance that that’s the case if you were born anywhere in Asia from the Pacific to the Caspian sea, it seems. A study conducted in that area found that approximately eight to ten percent of men were directly related to Genghis Khan.
This is traceable of course because fathers always pass their Y chromosomes to their sons, meaning that each man, from generation to generation, passed their Y chromosome to their son with minimal genetic variation. But how do we know that this was Genghis Khan’s Y chromosome?
Well, the truth is that we don’t. We can only guess based on how far back the haplotype (which is essentially the commonalities in Y chromosomes shared by these men) goes, and it seems that the haplotype growth exploded right around the time Genghis Khan was supposed to be practicing his baby-making abilities on whoever he came across.
This isn’t the only example of ancient men leaving behind long male lineages, however. The Manchu conquerors and the Han were also fans of this practice. They are dwarfed, however, by the sheer height of Genghis Khan’s family tree, suggesting that something else may have been driving its growth.
The possibility of the haplotype in question spreading like wildfire by chance rather than selection has been investigated as well. While it still remains a possibility, it is extremely unlikely: the haplotype doesn’t seem to suggest an inherent advantage of any biological nature. In fact, the probability of it being so widespread by chance has been calculated, and it’s astronomically small: less than 10 to the power of -237.
So, it’s definitely very likely that there was human intervention when it came to Genghis’s genetics being thoroughly spread through the continent. But wait… if Genghis Khan only had an estimated 1000 to 2000 children, how are there 16,000,000 direct descendants?
The numbers don’t add up… or do they?
Most people would realize that the leap necessary to go from 1000 or even 2000 to 16,000,000 isn’t going to happen overnight… or in the case of human lineage, over the course of several hundred years. But what’s important to realize is that it’s only unlikely if it happened by chance.
The explosive growth in the number of direct descendants of Genghis Khan suggests that more human intervention was required than previously recognized. And indeed, there was: through a process called social selection, it was ensured that Khan’s legacy would live on for hundreds of years to come.
Social selection differs from natural selection in the sense that, instead of the mutations (or lack thereof) of the next generation being left up to chance, the species itself intervenes and chooses the mutations based on certain social pressures.
This happens most in humans, of course, because we’re one of the few species intelligent enough to make such decisions. However, gene-editing (or even the knowledge of basic genetics) was something unavailable to the human race at the time, so if we wanted specific offspring, we had to improvise.
What resulted in the case of Genghis Khan was a sort of accidental eugenics: being a direct descendant of Genghis was a big deal at the time. It implied a certain prestige in quite a few cultures. For lack of better words, Genghis was just such a cool guy to people at the time that they all wanted to come directly from him.
The men who were all directly related to Khan were heralded as monolithic pillars of human achievement, and as such, they bred like crazy. People were so obsessed with Genghis Khan that, in some Muslim societies, people would claim direct descendance from the prophet Muhammad in an attempt to compete with those who were descended from Khan.
Genghis Khan lives on (unfortunately)
Because being descendent of Genghis Khan meant a heightened social status, the men who were endowed with his Y chromosome continued to produce as many more male-line descendants as they could. Thus, the massive Khan lineage was made possible.
Approximately 0.5% of the world’s population are descended directly from Genghis Khan, meaning that he is perhaps one of the most influential figures ever recorded. It kind of sucks that he had to be one of the most notoriously ruthless murderers of ancient history, though. Why couldn’t he have been admired for being an advocate of world peace or something? I’m disappointed in you, humanity.