DUBLIN - Scientists may have found Ireland's most fertile male, with more than 3 million men worldwide among his offspring.
Trinity College Dublin found that as many as one in 12 Irish men may be descended from 5th-century warlord Niall of the Nine Hostages.
His genetic legacy is almost as impressive as Genghis Khan, who has nearly 16 million descendants, said researcher Dan Bradley.
"It's another link between profligacy and power," he said.
The study tested Y chromosomes, passed on from fathers to sons, in samples from 800 Irish males. The results, published in the American Journal of Human Genetics, showed the highest concentration of related males in northwest Ireland, where one in five had the same chromosome.
Bradley said the study was similar to one in central Asia, where 8 per cent of men shared the chromosome linked to the Genghis Khan dynasty.
Bradley's team found that the "positives" from the original sample shared the same chromosome as the "Ui Neill" dynasty, which literally means descendants of Niall.
"The frequency [of the Y chromosome] was significantly higher in that genealogical group than any other group we tested," said Bradley, whose surname is also linked to the medieval warlord.
Other surnames linked to Niall include Gallagher, Boyle, O'Donnell and O'Doherty.
Niall reportedly had 12 sons, many of whom became powerful kings.
When international databases were checked, the chromosome also turned up in 2 per cent of all male New Yorkers.
High king and his hostages
* Irish: Niall Noigiallach
* A High King of Ireland who was active in the early-to-mid 5th century AD.
* He is believed to have died about 450/455.
* Said to have made raids on the coastlines of Britannia and Gaul.
* The fourth and youngest son of Eochaid Mugmedon, the Irish High King, and Cairenn, the enslaved daughter of a British king.
* Is said to have taken a hostage from each of the nine "tuatha" or petty kingdoms of "Airgialla".Alternatively, he took hostages from the five provinces of Ireland and one each from the Scots, Saxons, Britons and French, or from Dalriada, Caledonia, Strathclyde and Northumbria.
* During a raid on Britain, Niall is thought to have captured the future Saint Patrick and brought him in bondage to Ireland. Many years later Saint Patrick succeeded in escaping to Britain.After many years of study, he returned to Ireland and played an important early role in the conversion of the Irish to Christianity.