Although the fact that the Thoroughbred traces to three foundation stallions is widely recognized, a study performed in Ireland indicates the blood of one stallion is responsible for 95% of the breed's Y chromosomes.Scientists at Trinity College in Dublin traced the lineage of one million British Thoroughbreds back two centuries in what is believed to be the largest such study ever conducted.

The Darley Arabian along with the Godolphin Arabian and the Byerley Turk are recognized as the foundations of the Thoroughbred breed, but the Dublin study indicates the Darley Arabian is by far the most dominant.

"About 150 years ago, the Darley Arabian's genes raced away from all the others," Paddy Cunningham, the geneticist who led the study told the London Sunday Telegraph.

In 1704, Thomas Darley purchased the Darley Arabian, a bay who stood 15 hands, with a white blaze face and three white socks, in Aleppo, Syria, and sent him to his brother, John, who began using him for as a stallion in England the next year. Although he was bred to a limited number of mares, the Darley Arabian sired Flying Childers, the first great Thoroughbred racehorse, and Barlet's Childers, the great grandsire of Eclipse, the primary foundation of the Thoroughbred.

Both Flying Childers and Barlet's Childers were produced by Betty Leeds.