Scientists use retroviruses to unravel woolly history of sheep domestication

Apr 24, 2009
Scientists use retroviruses to unravel woolly history of sheep domestication

(PhysOrg.com) -- Scientists at the University of Glasgow have unravelled the woolly history of sheep domestication by examining retroviruses preserved in the animal’s DNA.

Livestock domestication, which was a fundamental step in human history, occurred approximately 11,000 years ago in Southwest Asia before spreading to Europe and the rest of the world.

Originally, were used primarily for their meat, but up until now it was not known where selection for secondary products like wool first took place. Also, no genetic marker was known to differentiate primitive breeds from modern ones.

However, a study led by Professor Massimo Palmarini, a virologist from the Faculty of Veterinary Medicine of the University of Glasgow, published in the , suggests that most likely, breeding of sheep for products such as wool also occurred first in Southwest Asia before spreading to Europe through secondary migrations that shaped the great majority of present-day sheep.

In coming to their conclusions, scientists examined the presence of a particular group of endogenous retroviruses (enJSRVs) within the DNA of 1,362 sheep from 133 different breeds of domestic sheep and their closest wild relatives.

Endogenous retroviruses are like genetic fossils; remnants of ancient infections caught by sheep and their ancestors thousands of years ago whose DNA has been integrated into the of the animal and then passed on to subsequent generations.

The sheep were tested for the presence of six enJSRVs and by comparing the prevalence of the different viruses amongst the sample group Prof. Palmarini and his colleagues were able to differentiate primitive breeds from the more recently domesticated animals.

The tests revealed that sheep previously recognised as primitive - such as the Soay sheep of St Kilda and the Orkney sheep in Scotland for example - were among some of the very first domesticated sheep. Other primitive breeds include the Mediterranean Mouflon and some sheep breeds present mostly in Scandinavia.

Interestingly, the Orkney sheep are more closely related to Nordic breeds in Scandinavia while Soay are linked to Mouflon, providing intriguing insights into ancient routes. Thus, primitive breeds were generally found on the periphery of Europe or in isolated areas.

Prof Palmarini said: “The primitive breeds survived the second migrations of improved breeds from Southwest Asia by returning to a feral or semi-feral state in islands without predators or by occupying land less prone to commercial exchanges.

“Most, if not all, of the breeds we identified as being of ancient origin were already considered primitive due to traits such as a darker, coarser fleece, moulting coat and presence of horns even in females.”

Scientists say that similar tests used in the study could be applied to other species and be used to identify and preserve rare primitive breeds of animals.

Prof Palmarini added: “By being able to differentiate primitive breeds from modern ones our study offers a rationale for identifying and preserving rare gene pools. We have also demonstrated how ERVs can be used as a new class of genetic markers to unravel the history of a domesticated species.”

The study involved scientists from twenty different countries including Dr. Bernardo Chessa, Prof Tom Spencer at Texas A&M University, and Dr Ingrid Mainland, an archaeologist at the University of Bradford. This work was primarily funded by the Biotechnology and Biological Research Council and Wellcome Trust.

More information: The paper ‘Revealing the history of sheep using retrovirus integrations’ is published in Science. http://www.sciencemag.org/cgi/content/abstract/324/5926/532

Provided by University of Glasgow

Explore further: Researchers successfully clone adult human stem cells

add to favorites email to friend print save as pdf

Related Stories

New tool to fast-track genetic gain in sheep

Jan 14, 2009

(PhysOrg.com) -- Scientists from CSIRO are part of an international team that today launched a new genomic tool which is set to transform the future selection and breeding of sheep around the world.

Study discovers secret of Scottish sheep evolution

Jan 17, 2008

Researchers from the University of Sheffield, as part of an international team, have discovered the secret of why dark sheep on a remote Scottish Island are mysteriously declining, seemingly contradicting Darwin’s evolutionary ...

Wanted: A sheep in sheep's clothing

Jun 06, 2006

Australian scientists say they are looking for the ugliest merino lambs they can find in a study that may challenge the dominance of synthetic fibers.

Recommended for you

Researchers successfully clone adult human stem cells

Apr 18, 2014

(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 ...

Researchers develop new model of cellular movement

Apr 18, 2014

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

For resetting circadian rhythms, neural cooperation is key

Apr 17, 2014

Fruit flies are pretty predictable when it comes to scheduling their days, with peaks of activity at dawn and dusk and rest times in between. Now, researchers reporting in the Cell Press journal Cell Reports on April 17th h ...

User comments : 0

More news stories

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

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 ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

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 ...