Breeding & Racing Magazine

Genetics Of The Grey Horse Unraveled

An international team led by researchers at Uppsala University in Sweden "has identified the genetic mutation that makes grey horses turn grey," reported thehorse.com. They have also "shown that these horses carry an identical mutation that can be traced back to a common ancestor that lived thousands of years ago". A grey horse is born coloured (black, brown or chestnut) & the greying process "usually starts during the 1st year; these horses are normally completely white by 6-8 years of age, but the skin remains pigmented". The process "resembles greying in humans, though it is ultra-fast in these horses". This new research demonstrates that "all grey horses carry exactly the same mutation, which must have been inherited from a common ancestor that lived thousands of years ago". Researcher Leif Andersson who led the study commented: "It is a fascinating thought that once upon a time, a horse was born that turned grey & subsequently white & the people that observed it were so fascinated by its spectacular appearance, that they used the horse for breeding so that the mutation could be transmitted from generation to generation." Today about 1-horse-in-10 carries the mutation for greying with age.