Is Nature Colorblind?

Author:  Charley Wang
Institution:  University of Toronto
Date:  April 2009

Why do domesticated dogs come in so many different shapes and colours, while wolves appear to be much similar to each other? Scientists have long theorized that humans had something to do with this increased phenotypic diversity within the species, and now researchers from the Universities of Uppsala and Durham have confirmed one piece of the puzzle in a study published in PLoS Genetics in March.

The results of the study focus on the melanocortin-1 receptor (MC1R) gene – one of the primary genes that control the colour of an animal's coat.

Researchers looked at the effect of genetic mutations on wild and domestic pigs from Europe and Asia. They found that while there were often some mutations in the MC1R gene in the wild pigs, the population as a whole remained a uniform black-brown colour which was best for camouflage. They theorized that changes to the coat colour were eventually selected against by predators and therefore did not survive long enough to procreate in the wild population.

Domestic pigs were found to have more MC1R mutations, often layered on top of one another. Since MC1R is not nearly as prevalent in the wild, its presence in domestic animals, researchers say, is proof that humans have been actively selecting coat colours for generations. In fact, the co-author of the study, Dr. Greger Larson from Durham University, says, "The Mesopotamians had different coloured farm animals 5,000 years ago . This study demonstrates that the human penchant for novelty stretches back thousands of years."

Thus, the study concludes that diversity in domestic animals is caused by human selection and shows how quickly external selection factors can change proteins, such as those that determine coat colour.

Written By: Charley Wang

Edited by: News and Features Editor Matt Getz and Professional Reviewer Lois Alexander

Published by Falishia Sloan