A new study on pigs, published January 16 in the open-access journal PLoS Genetics, reveals that the prime explanation for this phenomenon is that humans have actively changed the coat colour of domestic animals by cherry-picking and actively selecting for rare mutations and that this process that has been going on for thousands of years.
This result is important since it eliminates several other explanations for coat colour changes within domestic animals. One alternative idea was that wild type colour was lost because the pressure to remain camouflage was eliminated. This kind of change is analogous to the loss of vision in animals that live in complete darkness, such as caves. Others proposed that the change of colour was a by-product of domestication because some genes control both a trait under strong selection (e.g. behaviour) and colour. “Our study settles the debate by showing that the prime reason is intentional selection by humans”, says Leif Andersson at Uppsala University who led the study.
The researchers studied one of the key genes controlling coat colour in animals, the melanocortin-1 receptor (MC1R) gene, in both wild and domestic pigs from Europe and Asia. Though there were numerous differences in DNA sequence among the wild boar, none of them altered the protein function, and thus the coat colour remained camouflaged. This result demonstrates that mutations that do change the MC1R protein are quickly removed from wild populations in order to maintain camouflage colouration. In domestic pigs, however, nearly all observed DNA changes changed protein function leading to a wide variety of different colors.
Compared with the wild-type sequence, some of the domestic MC1R variants differed by up to three consecutive changes, thus revealing that domestic coat colour variation is not a recent phenomenon. “We know that the Mesopotamians were keeping track of differently coloured farm animals 5,000 years ago, and our results suggest black and white and spotted pets and livestock may have been around a lot longer than that”, said Greger Larson, a Research Fellow at Uppsala University and at Durham University.
So why did early farmers bother to change the coat of their livestock? One explanation could be 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.
The present study also sheds light on the process of molecular evolution. Charles Darwin was the first to recognize the importance of studying domestic animals as a model of evolution. An argument that has been raised against Darwin’s theory is that is impossible to create complicated structures like an eye, based on the underlying random process of mutation. “This study shows how quickly a protein can change under strong selection and how humans have “created” black-spotted pigs by selecting several consecutive mutations that have occurred by a random process”, says Leif Andersson.
This project was funded by the European Commission, the European Molecular Biology Organization, the Swedish Foundation for Strategic Research, and the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning.
Anneli Waara | alfa
New research recovers nutrients from seafood process water
31.10.2018 | Chalmers University of Technology
Plant Hormone Makes Space Farming a Possibility
17.10.2018 | Universität Zürich
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences