Consumption in the saddle
They really don't enjoy a good reputation: the "wild hordes" from the east are said to have brought death and destruction to Europe. But now Genghis Khan and his Mongols are being accused of another heinous act - spreading tuberculosis.
Novgorod, in the year 1223: "In that year, because of our sins, unknown tribes came, of which no one knows exactly who they are and where they came from." In fact, the Mongolian horsemen who, as impressively described in the Novgorod Chronicle, destroyed a numerically far superior Russian army in 1223 and thus set foot on European soil for the first time, must have appeared out of nowhere like a "scourge of God" and struck.
Just a few years earlier, in 1206, a rather insignificant chief named Temüdschin had united the quarreling Mongolian tribes in order to then conquer a world empire under the name of Genghis Khan, which was to be twice the size of today's USA. First he sent his riders to China, later it was the turn of distant Europe. In 1241, after the death of his son Ögödei Khan, the spook ended for the Europeans just as suddenly as it had begun.
The Mongol conqueror Genghis Khan (1162-1227)
The medieval Mongol invasion has burned itself deeply into people's memories. The image of Genghis Khan as a bloodthirsty butcher probably hardly does justice to historical truth, and his cavalry should not be blamed for all the ills of the world. But if Igor Mokrousov has his way, the Mongols could at least be partly to blame for the spread of a scourge of humanity: tuberculosis.
Together with his colleagues, the Russian microbiologist from the St. Petersburg Pasteur Institute tried to reconstruct the history of tuberculosis. To do this, the researchers compared the genetic profiles of a specific strain of the tubercle bacterium, known as the Peking genotype, with variations in the human Y chromosome. Oddly enough, Mycobacterium tuberculosis, which still kills an estimated two million people every year, shows a gender preference: About seventy percent of tuberculosis patients are male. Roughly speaking, the Y chromosome and tuberculosis pathogens are spread by men and should therefore share a comparable genetic fate.
In fact, the researchers were able to trace the tubercle far back: an estimated 40,000 to 30,000 years ago, a Homo sapiens population appeared in Central Asia whose Y chromosome reflects the so-called K-M9 polymorphism. Mycobacterium tuberculosis probably felt comfortable with them.
Together with its human host, the germ migrated northeast towards Siberia between 30,000 and 20,000 years ago and spread throughout East Asia between 10,000 and 4,000 years ago. About 800 years ago, when Genghis Khan turned his gaze west, the Peking genotype of the bacterium appeared in Europe. Within the last 300 years it finally reached South Africa - presumably in the luggage of Chinese and Indonesian seafarers.
It remains to be seen whether Genghis Khan actually promoted the worldwide spread of consumption. However, the Mongol prince is not denied a particular biological significance: during his conquests he is said to have fathered so many children that at least eight percent of the male population between the Pacific Ocean and the Caspian Sea can see themselves as his direct descendants.
He himself died neither of tuberculosis nor in the turmoil of battle, but succumbed to a minor mishap in 1227: the great ruler fell from his horse while hunting.
