Scientists have traced the origin of the 'speed gene' in Thoroughbred racehorses back to a single British mare that lived in the United Kingdom around 300 years ago, according to findings published today in the scientific journal Nature Communications. The origin of the 'speed gene' (C type myostatin gene variant) was revealed by analysing DNA from hundreds of horses, including DNA extracted from the skeletal remains of 12 celebrated Thoroughbred stallions born between 1764 and 1930. "Changes in racing since the foundation of the Thoroughbred have shaped the distribution of 'speed gene' types over time and in different racing regions,"...