One in every 200 men alive today is a relative of Genghis Khan. An international team of geneticists has made the astonishing discovery that more than 16 million men in central Asia have the same male Y chromosome as the great Mongol leader.

It is a striking finding: a huge chunk of modern humanity can trace its origins to Khan's vigorous policy of claiming the most beautiful women captured during his merciless conquest.

'One thirteenth century Persian historian claimed that within a century of Khan's birth, his enthusiastic mating habits had created a lineage of more than 20,000 individuals,' said team leader Dr Chris Tyler-Smith. 'That now appears to account for around 8% of the men in central Asia.'

The team, from Britain, Italy, China and Uzbekistan, took tissue samples from 2,000 men from central Asia, and studied each one's Y chromosome, the genetic package that confers maleness and is passed only from father to son.

'Y chromosomes belonging to different men vary slightly. One in every 5,000 DNA units is not the same,' said Tyler-Smith. 'But when we looked at our results, we found a huge group that did not show any differences. We were absolutely amazed.'

One researcher, Tatiana Zerjal, even suggested they had found the genetic footprint of Khan. 'It was just a joke,' added Tyler-Smith. 'Then we began to look more closely at our results, and realised it was the only really feasible explanation for what we had found.'

First the team, whose results are published in the latest edition of the American Journal of Human Genetics, found the geographical spread of possessors of the chromosomes almost exactly matched that of Genghis's empire, which stretched from China to the Middle East. Then they discovered that all of these men shared a common ancestor. Again the answer was consistent with the march of Khan, who lived between 1162 and 1227.

'There are only two ways a single Y chromosome can make such a mark on a population,' Tyler-Smith said. 'The chromosome could in some way confer its owners with some biological advantage. But given that a Y chromosome is little more than a biochemical switch that turns an embryo into a male child, it is hard to see how it could have such an effect.

'The other explanation is that its original possessor had some incredible social advantage over other Y chromosome possessors, allowing its owner to pass it on, over and over again. Khan fits that bill perfectly. He had many wives, and was enthusiastic in his attentions to other women.

When Mongol armies attacked, their spoils were shared among the troops and officers, with one exception. The most beautiful women were reserved for Khan.

The study also sided with the Hazara people of northern Pakistan, whose claim to be direct descendants of Khan is derided by historians. It found the Hazaras' Y chromosomes were identical to those they had already linked to Khan.

'It is not the first time the oral tradition has been proved more reliable than academic treatise,' he added. 'It takes the power of genetics to prove it, however.'