Rare White Horses: It's All in the Genes

Author:  Ramlagan Nadia
Date:  August 2008

It is the quintessence of fairy tales- a knight in shining armor bravely galloping to the rescue on his white horse. A team of scientists at Uppsala University in Sweden has now discovered the genetic mutation that causes a horse's hair to "grey", or turn white.

The results have important implications for cancer research, as the mutation in horses is linked to the development of melanoma, a type of cancer in humans that causes deadly tumors of pigment cells to form on the skin. Since over 75% of white horses over 15 years old have some level of melanoma, identifying the mutation is a step closer towards determining the molecular pathway responsible for tumor growth.

Horses with the mutation are born normally colored, with coats of brown, chestnut, or black. But by the time the baby horse is 6 to 8 years of age, all of its hair has morphed into a dazzling white. The process is a bit like aging in humans, but the tuft of white hair on your grandfather's head took more or less a lifetime to get there, whereas graying occurs extremely fast in horses.

Today these snowy horses are a rarity; about 1 horse out of 10 carries the mutation. Researchers were able trace its genetic origin thousands of years back to a common ancestor, whom all white horses inherited the exact same mutation from.

"It is a fascinating thought that once upon a time a horse was born that turned grey and subsequently white and 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," said Leif Andersson who led the study.

Written by Nadia Ramlagan

Reviewed by Pooja Ghatalia

Published by Pooja Ghatalia.