Thoroughbred racehorses are not as pure and exotic as first thought, claim scientists, who found a large proportion are cross- breeds that descend from common Irish and British horses.
Detailed records show that the Thoroughbred breed emanates from a handful of Arabian stallions imported in the 17th century to produce super-fast animals.
It was thought a large proportion of the mares were also shipped in from abroad to create the elite steeds.
But researchers at the University of Cambridge have discovered this is not the case and most mares came from native stock.
The scientists led by Dr Mim Bower analysed the DNA of 1929 horses and found that just 8pc of their maternal genes come from abroad.
The rest of the female breeding stock must have been native.
That means, far from being exotic, the vast majority of the DNA that makes up a Thoroughbred is home-grown.
"In the 17th and 18th centuries it was all about the boys," said Dr Bower. "They didn't realise that genetically the mare was just as important.
"As a result most of the founding mares came from Britain and Ireland. They are not these exotic foreign creatures everyone thinks they are.
"Having said that they were not just any mares they were themselves descended from the fastest horses in the country."
Thoroughbreds have strict bloodlines and family trees and have been exported all over the world.