According to a reliable, serious and peer-reviewed scientific study, a large part of the Eurasian population is descended from the great Mongol emperor Genghis Khan. The study, dating from 2010, had a great media impact that made him the grandfather of humanity. Today, we know that Genghis Khan is not responsible for it.
Genghis Khan is more legend than man. We don’t even know for sure when he was born: historians agree that it was between 1155 and 1167. After the Mongol army subdued more land and people in twenty years than the Romans did in four hundred, the great warrior died in August 1227 and was buried in secret.
Like that of Alexander the Great, his body has been lost to legend and tradition. All projects and expeditions that have attempted to locate his tomb have failed. Since we do not have the body or any tangible trace of his passage on earth, we know nothing about his DNA and even less about his Y chromosome. However, a scientific study has awakened Genghis Khan from the dead.
A common Y chromosome?
The DNA of the inhabitants of Central Asia contains fragments from all over the planet. However, in the late 1990s of the last century, it was one of the least studied regions of the world in genetic terms. From this gap arose in 2003 an article on population genetics, led by Oxford University biochemist Tatiana Zerjal, focusing on the Y chromosome.
Zerjal and his colleagues used fragments of Y-chromosome DNA from more than 2,000 Asian men. They compared it to populations around the world and found something strange: In their sample of Asian men, there was a haplotype that was too common to make sense. A haplotype is a group of genomic variants (or polymorphisms) that tend to be inherited together.
8% of men had this Y chromosome with a haplotype so exceptional that they turned to the world of galaxies to give it a name: star cluster, which in astronomy designates a group of stars whose members are linked by a mutual gravitational attraction.
If their sample was representative, it meant that those living in the territories of the former Mongol empire, or 0.5% of the world’s population, shared the same Y chromosome. They must therefore all be related through the paternal line.
Chance alone makes this too unlikely. There must have been some selective pressure. But the Y chromosome is very small, so the chances of one of its genes conferring a clear competitive advantage in survival were extremely low.
The other most plausible reason was that a man had been extraordinarily fertile.
The fertile man who lived 1,000 years ago
In the study led by Tatiana Zerjal, it was estimated that the most recent common ancestor of all men sharing this Y chromosome lived in Central Asia about 1,000 years ago, at the time of the great Genghis Khan.
As one thing leads to another, in the article they suggest that all carriers of this Y chromosome belonged to the lineage of the Mongol emperor. In other words: there are currently between 40 and 45 million people on the planet who are direct descendants of Genghis Khan.
There was no shortage of reasons: Genghis Khan’s personal traveling brothel consisted of thousands of women whom he repudiated or incorporated as he conquered new territories, which meant that his DNA spread across a vast region of the world.
Genghis Khan had five daughters and four sons with his main wife, and countless others with the minor wives and concubines he acquired through his conquests.
Their genes were thus widely spread throughout Central Asia. At least in theory, because the truth is that the fundamental proof that they were his was missing: the DNA of the promiscuous Mongol warlord.
In search of Genghis Khan’s DNA
Genghis Khan’s body had to be found. More than 10,000 volunteers spent a total of three and a half years combing through satellite images for any trace of his grave. An expedition was then organized to explore the 55 most promising sites that emerged from this virtual search. The remains did not appear.
In 2004, five graves were discovered in Tavan Tolgoi, eastern Mongolia. The objects they contained and the quality of the wood used for the coffins clearly pointed to Genghis Khan’s family. Scientists analyzed the DNA of the skeletons, but the Y chromosome they found in the buried men was not the one from the “star cluster.”
Another group investigated a clan in China that was said to be descended from Toghan, the sixth son of Genghis Khan. But its Y chromosome turned out to be different from the one described in Tatiana Zerjal’s paper and the one found in the Tavan Tolgoi excavations. They had nothing to do with Genghis Khan’s lineage.
The legend crumbles: Genghis Khan was not there
The problem with any population DNA sample is that you have to choose it and trust that it is representative. In the research that led to Tania Zerjal’s publication, the sample was 2,123 men. In 2018, a study expanded the sample to 18,000 individuals from a larger region of Central Asia.
By obtaining a more precise image, they confirmed the existence of the haplotype starbut they found that it was not 1,000 years old, but 2,600 years old, which is to say that it was much older than Genghis Khan himself. Being so old, this genetic heritage had plenty of time to spread among the tribes of Central Asia and to disperse when the region became the heart of the Silk Road that connected Europe to Asia. The Silk Road facilitated a great deal of genetic mixing between populations.
We Eurasians are not direct descendants of Genghis Khan, but we all carry in our cells the indelible trace of the migratory route that our ancestors followed when leaving Africa. As for the great Khan, his face, his bones and his own DNA remain hidden where oblivion dwells.
Manuel Peinado Lorca is Professor Emeritus of Life Sciences. Director of the Royal Botanical Garden of the University of Alcalá, University of Alcalá
This article was originally published on The Conversation. Read the original.
