Irish researchers have found that horses with a specific mutation in the gene called myostatin (MSTN) have improved athletic performance.

"A variety of mammalian species with specific MSTN variants have characteristics of increased muscle mass," explained lead researcher Emmeline Hill, PhD, from the Animal Genomics Laboratory at University College Dublin, Ireland.

She said whippet racing dogs provide an example: Dogs that are heterozygous (have one copy) for a specific variant of the MSTN gene have significantly greater racing ability than dogs that are either homozygous (have two copies) for the mutation or dogs with no copies of the mutation.

Since this sequence in Thoroughbred racehorses had not yet been examined, Hill and colleagues analyzed DNA for variations in 148 Thoroughbred horses