Featured Research

from universities, journals, and other organizations

Genetics Of White Horses Unraveled: One Mutation Makes Ordinary Horses Turn Grey, Then White, Very Young

Date:
July 23, 2008
Source:
Uppsala University
Summary:
White horses are colored horses that turn grey, then white, at a very young age. The white horse is an icon for dignity which has had a huge impact on human culture across the world. Scientists have now identified the mutation causing this spectacular trait and show that it can be traced back to an ancestor that lived thousands of years ago. The study is interesting for medical research since this mutation also increases the risk of melanoma.

A high contrast shot of a white Andalusian stallion in the sun against a black background.
Credit: iStockphoto/Baldur Tryggvason

The white horse is an icon for dignity which has had a huge impact on human culture across the world. An international team led by researchers at Uppsala University has now identified the mutation causing this spectacular trait and show that white horses carry an identical mutation that can be traced back to a common ancestor that lived thousands of years ago.

The study is interesting for medical research since this mutation also increases the risk for melanoma.

The great majority of white horses carry a dominant mutation that results in rapid greying with age. A "Grey" horse is born coloured (black, brown or chestnut) but the greying process starts very early in life -- during its first year. These horses are normally completely white by six to eight years of age but the skin remains pigmented. Thus, the process resembles greying in humans but the process is ultrafast in these horses. The research presented now 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.

"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," says Leif Andersson who led the study. Today about one horse in ten carries the mutation for Greying with age.

It is obvious that humans across the world have greatly valued these white horses as documented by the rich collection of stories and paintings featuring white horses. In the new paper, this admiration is illustrated with a reproduction of a painting from the late 17th century of the Swedish king Karl XI on his white horse Brilliant.

The Grey horse is also very interesting from a medical point of view since the mutation also predisposes for the development of melanoma. About 75% of Grey horses older than 15 years of age have a benign form of melanoma that in some cases develops into a malignant melanoma. Thus, the new study has also offered insight into a molecular pathway that may lead to tumour development.

"We propose that the Grey mutation stimulates growth of melanocytes and that this leads to a premature loss of the melanocyte stem cells needed for hair pigmentation whereas the mutation promotes an expansion of some of the melanocytes causing skin pigmentation," says Leif Andersson.

Domestic animals constitute extraordinary models for evolution of biological diversity, as recognized by Charles Darwin. The white horse is a beautiful illustration of the importance of regulatory mutations as a major underlying mechanism for phenotypic diversity within and between species. The Grey mutation does not change any protein structure but it affects the genetic regulation of two genes. The researchers found that the white horses carry an extra copy of a DNA segment located in one of these genes.

"It is very likely that regulatory mutations like the one we found in these white horses constitute the dominating class of mutations explaining differences between breeds of domestic animals as well as between species like humans and chimpanzee," concludes Leif Andersson.

The paper is published on July 20 on the website of Nature Genetics.


Story Source:

The above story is based on materials provided by Uppsala University. Note: Materials may be edited for content and length.


Cite This Page:

Uppsala University. "Genetics Of White Horses Unraveled: One Mutation Makes Ordinary Horses Turn Grey, Then White, Very Young." ScienceDaily. ScienceDaily, 23 July 2008. <www.sciencedaily.com/releases/2008/07/080720150203.htm>.
Uppsala University. (2008, July 23). Genetics Of White Horses Unraveled: One Mutation Makes Ordinary Horses Turn Grey, Then White, Very Young. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2008/07/080720150203.htm
Uppsala University. "Genetics Of White Horses Unraveled: One Mutation Makes Ordinary Horses Turn Grey, Then White, Very Young." ScienceDaily. www.sciencedaily.com/releases/2008/07/080720150203.htm (accessed October 20, 2014).

Share This



More Plants & Animals News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins