THEY seem the unlikeliest of relatives. One was a fearsome warlord whose name became a byword for savagery. The other is a mild-mannered accountancy academic from Florida.

Yet Tom Robinson, 48, has become the first man outside Asia to trace his ancestry directly to Genghis Khan, the 13th-century Mongol leader whose empire stretched from the South China Sea to the Persian Gulf.

And, since his paternal great-great-grandfather emigrated to the United States from Windermere, Cumbria, many more descendants are probably scattered across the Lake District.

Genetic tests have revealed that Mr Robinson, a professor of accountancy at the University of Miami, shares crucial portions of his DNA with the Mongol ruler.

He has little in common with his infamous ancestor. He is not a keen horseman. Though a Republican, his politics are moderate. And while Genghis Khan may have fathered thousands of children, Professor Robinson and his wife, Linda, have no offspring.

“I’m not sure we have too many similarities,” he said. “I obviously haven’t conquered any countries, and though I’ve headed up accounting groups, I’ve done nothing as big as Genghis Khan.

“I’m proud to have such an interesting ancestor. I’ve been reading a lot about him since I found out about the link, and it does seem that his reputation is a little unfair.

“He conquered a lot of countries, but he had a pretty good system of government.”

Professor Robinson’s genetic past was uncovered by Brian Sykes, Professor of Human Genetics at the University of Oxford. His company, Oxford Ancestors, offers genetic tests to help people to trace their family trees.

Samples of Professor Robinson’s DNA were first taken four years ago. Tests suggested that his paternal forebears came from the Caucasus, while his mother’s ancestors originated in the Pyrenees.

Then a study in 2003 suggested that up to 16 million people worldwide — and 8 per cent of Asian men — were descended from Genghis Khan, and Professor Sykes decided to trawl through his database of approximately 25,000 male clients for a match.

The link is revealed by the Y chromosome, a packet of DNA that determines male sex, which is passed down from father to son. Men who share a Y chromosome are invariably descended from the same man at some point in the past, and the accumulation of mutations can be used to date the common ancestor. Women do not have a Y chromosome, so they cannot be tested in the same way, although millions are likely also to be descended from the warlord.

The 2003 study found that large numbers of Asian men from the regions that once made up the Mongol empire shared a single Y chromosome, and that this originated in a man who lived in the early 13th century.

Genghis Khan lived from about 1162 to 1227 and fathered hundreds or even thousands of children as his armies swept across the continent. This makes him by far the most probable source of the common chromosome.

Professor Sykes said: “Genghis Khan may have been the most successful male ever at spreading his genes. He would have passed his Y chromosome on to his sons and grandsons, who inherited his empire and with it an opportunity to spread it even further.

“We knew it exists widely in Asia today, but I was sure it must have moved further afield as well. Tom Robinson is the first man we’ve found who has it who is from a European or American background.”

Oxford Ancestors looked for Genghis Khan’s genetic signature by examining Y chromosomes for nine characteristic DNA markers. Professor Robinson’s Y chromosome is an exact match for eight of the nine markers, and one mutation is expected over the 800 years that separate him from the Mongol ruler.

“It is a very precise match,” Professor Sykes said.

Professor Robinson’s research into his family tree shows that his paternal great-great-grandfather, John Robinson, emigrated from the Windermere area to Illinois, placing the Genghis Khan chromosome firmly in Britain in the relatively recent past.

Ravdan Bold, the Mongolian Ambassador to the US, is holding a reception in Professor Robinson’s honour in Washington DC next month.

Any man who is interested in finding out whether he is descended from Genghis Khan can be tested by Oxford Ancestors for £195.

FROM MONGOLIA TO MIAMI

In modern Mongolia he is regarded as a national hero

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