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
Raiding the rape field
23.05.2018 | Julius-Maximilians-Universität Würzburg
New technique reveals details of forest fire recovery
17.05.2018 | DOE/Brookhaven National Laboratory
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences