Genetic study of black chickens shed light on mechanisms causing rapid evolution in domestic animals

Dec 22, 2011

The genetic changes underlying the evolution of new species are still poorly understood. For instance, we know little about critical changes that have happened during human evolution. Genetic studies in domestic animals can shed light on this process due to the rapid evolution they have undergone over the last 10,000 years. A new study published today describes how a complex genomic rearrangement causes a fascinating phenotype in chickens.

In the study published in researchers at Uppsala University, Swedish University of Agricultural Sciences, North Carolina State University and National Chung-Hsing University have investigated the genetic basis of fibromelanosis, a breed characteristic of the Chinese Silkie chicken. This trait involves a massive expansion of pigment cells that not only makes the skin and comb black but also causes black . Chickens similar in appearance to the Silkie were described by Marco Polo when he visited China in the 13th century and Silkie chickens have a long history in Chinese cuisine and .

We have shown that the causing fibromelanosis is a complex rearrangement that leads to increased expression of Endothelin 3, a gene which is known for promoting the growth of , explains Ben Dorshorst the post-doctoral researcher responsible for the work.

The research group led by Leif Andersson has by now characterized a number of traits in domestic animals, and a clear trend is emerging, namely that genomic rearrangements have contributed significantly to the of domestic animals. Other examples include Greying with age in horses and mutations affecting the size and shape of the comb in chickens.

We have good reason to believe that such rearrangements have also played a significant role in the evolution of other species, including ourselves, concludes Leif Andersson.

The researchers also studied other chicken breeds where fibromelanosis occurs, including the Bohuslän-Dals svarthöna breed from Sweden, and they found that all fibromelanotic breeds carried the exact same very unusual mutation. This finding is consistent with anecdotal evidence suggesting that this Swedish breed of chicken inherited their black skin and internal connective tissue color from Asian chickens that were first brought to Norway by a sailor on the East Asian trade routes centuries ago. This is a nice example of how humans have distributed a single novel mutation with an interesting effect when they developed breeds of domestic animals around the world.

It is obvious that humans have had a strong affection for biological diversity in their domestic animals, says Leif Andersson.

Explore further: New insights into how different tissues establish their biological and functional identities

More information: Dorshorst B, Molin A-M, Rubin C-J, Johansson AM, Stromstedt L, et al. (2011) A Complex Genomic Rearrangement Involving the Endothelin 3 Locus Causes Dermal Hyperpigmentation in the Chicken. PLoS Genet 7(12): e1002412. doi:10.1371/journal.pgen.1002412

add to favorites email to friend print save as pdf

Related Stories

Darwin was wrong about the wild origin of the chicken

Feb 29, 2008

Charles Darwin maintained that the domesticated chicken derives from the red jungle fowl, but new research from Uppsala University now shows that the wild origins of the chicken are more complicated than that.

Study shows how chickens keep their cool

Mar 15, 2011

Its head looks like a turkey's, its body resembles a chicken's – now scientists can explain why one of the poultry world's most curious specimens has developed such a distinctive look.

Canine morphology: Hunting for genes and tracking mutations

Mar 02, 2010

Why do domestic dogs vary so much in size, shape, coat texture, color and patterning? Study of the dog genome has reached a point where the molecular mechanisms governing such variation across mammalian species are becoming ...

Recommended for you

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Plants with dormant seeds give rise to more species

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.