The question of Genghis Khans genetic history arose in the 2000s, when academics began looking into how many descendants belonged to the fearsome leader. Researchers have tracked Khans Y chromosome and discovered a dizzying number of relations, tracing Genghis Khans genetic path all the way from China to Europe. Many of Genghis Khans sons went on to become conquerors themselves. Mongols settled in these areas, taking local women as wives and concubines.The Estimated Number of Khans DescendantsMongol Empire Greatest Expansion Source: WikimediaKhans far-flung conquests and family led to this astonishing number: 16 million. Or, 0.5% of the worlds men are thought to possess the Y chromosome of this ruthless, adaptable ruler. How so many people related to Genghis Khan or his family need some explanation. First, invasion and conquest established the genetic footprint. Simply taking so much territory and people into their sphere meant intermingling.The Mongols also practiced polygamy, a common practice of the time. Genghis Khan had numerous wives or concubines. Whether gained by alliances, conquest, rape, or tribute, the Khan and his sons produced many children ensuring the spread of their Y chromosome.Inadvertently, the father-to-son system (patrilineal) established by Khan ensured that his lineage remained dominant. Like any smart ruler, Khan sought to keep those close loyal. He allocated conquered lands to his sons and generals.Khan encouraged marriage between the Mongol elite and local nobles. Wisely the Mongol ruler gave important administrative or military positions only to trusted kin. With all this entwined and the Empires duration guaranteed, Khans DNA would endure.Where Genghis Khans Genetic Legacy Is More CommonMongol Genes Found in Tajikistan Source: Molecular Biology and EvolutionGenetic pockets inevitably formed during the Mongol Empire, as Mongols and locals settled along trade routes such as the Silk Road. And this legacy trickled down to the modern era. Given Genghis Khans reproductive success, he or his descendants spread his genes to far-flung locations, including the Russian Caucasus, Tajikistan, and China. These descendants increased over time, growing into thousands and later millions, as discovered in several genetic studies over the last thirty years.An example of tracking the Y chromosome is in Tajikistan. An essential part of the Silk Road, the Mongol armies devastated Tajikistan, especially to the north. The following image illustrates where Mongol DNA traces are found.Ethnic Groups with Khans DNAHazaras Men,1840 by Atkinson. Source: WikimediaAs with Khans genetic hotspots, the Y chromosome is more prevalent in certain ethnic groups than in others. While Khans DNA is found in several areas, certain groups contain a higher percentage. With this, the average reader will get an inkling of the population bearing Khans male-only descended DNA. At 0.5% worldwide, thats a lot. Scientists believe this DNA primarily originates from Khans Mongol sons or other family members.Mongolia tops the list, with an estimated 35% of males bearing Khans DNA. Apart from this obvious Mongol stronghold, other groups with particularly high percentages are in Kazakhstan and Uzbekistan. Others, like the Hazaras of Afghanistan and Pakistan, have significant numbers of men bearing Genghis Khans unchangeable Y chromosome, perhaps as much as 30%. Afghanistan had become a crossroads due to the Silk Road, which attracted Khans armies. The Y chromosome percentage drops sharply, with Northern China showing that about 8% carry Khans lineage.Genghis Khans Y Chromosome LineageA manuscript showing Genghis rewarding the Four Dogs and other followers at the Kurultai of 1206 CE. Source: BnFThe quest to track Khans descendants began with a 2003 study by Tatiana Zerja et al. (other researchers), titled The Genetic Legacy of the Mongols, which examined sixteen groups across Central Asia, from the Pacific to the Caspian Sea. This study investigated the distinctive Y chromosome linked to Genghis Khan. The researchers determined that 8% of men in the region carried it. Later, the research methods and results would be disputed. But Genghis Khans Y chromosome is no doubt present.Later studies confirmed and refined the 2003 study. With the Y chromosomes paternal descent serving as a unique data tracker, newer technology yielded improved genetic results. Specific populations were identified with precise results, and Khans DNA was shown. This led to a higher yield, suggesting that Khans ancestors may have numbered 17 million! What began as a genetic study transcended the fact that one of historys significant figures had millions of ancestors.