Colored furs

28januari2009
Source: uu.se
The furs of our dogs, cows and other domesticated animals, come in many colors and patterns, while the furs of wild animals are much more uniform. Researchers in Sweden and the United Kingdom discovered why. The results were recently published in PLoS Genetics.
Scientists used to believe that the ‘wild’ color disappeared in wild animals along with the need to camouflage. An alternative reason would be that the change in color is simply a byproduct of domestication. Genes, for example, can influence several features, such as color and behavior. But now, researchers discovered that the variation in color was caused by oriented selection.

Researchers of the University of Uppsala (Sweden) and Durham University (UK) focused on the colors of wild and domesticated pigs. In wild pigs, a mutation in the gene that determines the color of the fur (MC1R) is quickly removed from the population. Camouflage is too important. In domesticated pigs, however, the MC1R gene had sometimes already undergone three mutations, leading to a great diversity of colors. This shows that variation in color is not a recent phenomenon. In ancient Mesopotamia (5000 years ago), farmers already kept count of the different colors of the animals. Black and white spotted animals may even date from a much earlier period.

What may have caused the selection, researchers can only guess. It may have been easier for the farmers to trace their animals when they had a different color. It may also have been mere curiosity. The different colors of their livestock may have been a sign to other people: look how much my domesticated animals differ from wild animals!

In dogs and cows, it is the same gene which causes the variation in the colors and patterns of the fur.