Human love of novelty drove animal colour

Humans have actively changed the coats of domestic animals by cherry-picking rare genetic mutations over thousands of years, causing variations such as different colours, bands and spots, a new study proves for the first time.

Variation in domestic animal colour could be down to early farmers' fascination with biological novelty and diversity

The study on wild and domestic pigs by Uppsala and Durham Universities, published in the open access journal PLoS Genetics, can also explain the evolution in the coat colours of all domesticated animals, like cows and dogs, as they all express the same melanocortin-1 receptor (MC1R) gene - a key gene that controls coat colour in animals.

Study co-author Dr Greger Larson, of Durham University's Department of Archaeology, said: “The Mesopotamians had different coloured farm animals 5,000 years ago, and in that regard they were no different to Paris Hilton, who loves pink Chihuahuas, or anyone else with animals with unusual coat colours. This study demonstrates that the human penchant for novelty stretches back thousands of years.”

The team observed DNA mutations in both wild and domestic pigs. However, in the wild pigs - which have a uniformly black-brown coloured, highly camouflaged coat - none of the mutations altered the protein or the coat colour. Researchers say it is likely that any mutations that resulted in coat colour changes were rapidly selected out of the population by predators, ensuring that the mutation disappeared.

In the domestic pigs nearly all of the observed mutations changed the protein. In some cases there were three consecutive, or layered mutations - evidence that the initial mutations have been around for a long time. Researchers say this shows that the mutations and resulting coat colour changes were actively encouraged and perpetuated by farmers over thousands of years.

Dr Greger Larson added: “Early farmers may have decided to change the coat of their livestock for a number of reasons. One is that it facilitated animal husbandry since it is easier to keep track of livestock that are not camouflaged. Another could be that it has acted as a metaphor for the improved characteristics of the early forms of livestock compared with their wild ancestors. A third possibility is that the early farmers were as amused and as taken with biological novelty and diversity as we are today.”