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 Cereals use chemical defenses in a multifunctional manner against different herbivores
06.12.2018 | Max-Planck-Institut für chemische Ökologie

nachricht Can rice filter water from ag fields?
05.12.2018 | American Society of Agronomy

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: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Electronic evidence of non-Fermi liquid behaviors in an iron-based superconductor

11.12.2018 | Physics and Astronomy

Topological material switched off and on for the first time

11.12.2018 | Materials Sciences

NIST's antenna evaluation method could help boost 5G network capacity and cut costs

11.12.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>