Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Why domestic animals changed coat

16.01.2009
You notice it in your everyday life, the bewildering diversity in coat colour among our pigs, dogs and other domestic animals. This stark contrasts with the uniformity of colour within wild animals.

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
Further information:
http://www.uu.se

More articles from Agricultural and Forestry Science:

nachricht Fighting a destructive crop disease with mathematics
21.06.2017 | University of Cambridge

nachricht Unusual soybean coloration sheds a light on gene silencing
20.06.2017 | University of Illinois College of Agricultural, Consumer and Environmental Sciences

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>