Scientists have discovered that every thoroughbred horse in the world - of which there are approximately 500,000 - is descended from a group of only 28 animals imported 300 years ago to Britain and Ireland. Scientists have identitifed that this tiny elite was the ultimate source of DNA in today's racehorses, with just 10 individuals contributing to 80% of the gene pool. The research has been carried out by Trinity College Dublin and shows that every male horse has a Y chromosome - being passed on exclusively from father to son - that originated with one of three stallions.
James Darley, a British consul in Aleppa, Syria, brought the stallion known as Darley Arabian to Britain at the beginning of the 18th Century. Around 95% of male thoroughbreds can trace their ancestry to this founding father.
The remaining 5 per cent is attributed to two other horses from the same period - the Byerley Turk, captured from a Turkish Army offiicer at the Battle of Buda in Hungary and ridden in the Irish wars; and Godolphin Barb, born in Yemen and given to King Louis XV before being bought by the Earl of Godolphin.
Interestingly there were also 25 ancestral mares that founded around 14 per cent of all maternal lines - the most important being Tregonwell's Natural Barb Mare.
Scientists belive that this high degree of inbreeding has boosted the athletic performance of racehorses to the point that it is believed that the best horses are performing at a level close to the species' physiological limit. This is particularly because breeders have selected so successfully for genes that improve speed, endurance, lung capacity and muscle strength.
These genetic insights from Professor Cunningham will help researchers to determine which genes are most heavily involved in athletic ability and could lead ultimately to tests to predict potential for prospective buyers. This research also enables scientists to identify genes responsible for inherited disorders such as broken bones, tendon damage and bleeding lungs.
The team carried out the research by taking DNA from 211 thoroughbreds to track their genetic relationship to one another. This revealed a match for 47 per cent of their DNA. Racehorse breeding began during the reign of Charles II in the late 17th century when horses from Arabia and Egypt were imported and bred. In 1791 James Weatherby published the General Stud Book catloguing these pedigrees and founding todays Weatherbys. An estimated million thoroughbreds have existed in the General Stud Book's history and about half of these are alive today.