While it may be hard to believe, research conducted by the University College Dublin, Equinome Ltd and the University of Cambridge suggests that the modern Thoroughbred sprinter got its speed from a gene from a single Shetland pony mare that lived in the UK about 300 years ago.  The findings were published in the scientific journal, Nature Communications.

The research was led by Dr Emmeline Hill, a genomics scientist at University College Dublin (UCD) and Dr Mim Bower, an archaeo-geneticist at the University of Cambridge. The other institutions contributing to the study were Equinome Ltd, the Swedish University of Agricultural Sciences, the Smurfit Institute of Genetics, and the Russian Academy of Sciences. The research was supported by grants from The Horserace Betting Levy Board, Leverhulme Trust, Cambridge Overseas Trust and Science Foundation Ireland.

The “speed gene” — MSTN — was first identified in 2010.  It is associated with muscle growth and comes in two varieties, or alleles: C and T. Horses with two copies of the C allele are fast, short-distance sprinters. Horses with one C and one T tend to be strong middle-distance runners. And T/T horses have less speed, but greater stamina.

In this recent study, scientists analyzed DNA from hundreds of horses, including DNA extracted from the skeletal remains of 12 celebrated Thoroughbred stallions born between 1764 and 1930.

According to Emmeline Hill, a genomics scientist at University College Dublin:

“We traced the economically valuable gene variant by determining ‘speed gene’ type in almost 600 horses from 22 Eurasian and North American horse breeds, museum bone and tooth specimens from 12 legendary Thoroughbred stallions, 330 elite performing modern Thoroughbreds from 3 continents, 40 donkeys and two zebras.”

The study identified the Shetland breed as having the highest frequency of the C type gene variant. The Shetland represents local British horse types, which were the preeminent racing horses prior to the formal foundation of the Thoroughbred.

By comparing the diversity of the chromosomes around the C and T type gene variants researchers found only a single C type compared to 11 different T type gene variants, meaning that the ‘speed gene’ entered the Thoroughbred breed just once.

“The results show that the ‘speed gene’ entered the Thoroughbred from a single founder, which was most likely a British mare about 300 years ago when local British horse types were the preeminent racing horses, prior to the formal foundation of the Thoroughbred racehorse,” said Dr Hill.

So next time you look at a Shetland pony, don’t think Thelwell, think Seattle Slew.