Rare chickens such as the ‘Scots Dumpy’ which was used by the Picts to warn of the approach of the Roman Army, could be brought back from the brink of extinction by Edinburgh University.
Scientists have genetically engineered chickens which can act as surrogates and lay the eggs of other rare breeds.
The surrogates themselves are sterile and so cannot produce their own offspring. But when the stem cells from rare chicken breeds are implanted into their reproductive tissue, they go on to produce eggs and ultimately chicks from the threatened species.
It is part of a wider project to create a ‘Frozen Aviary’ of stem cells from birds so that populations could be brought back to life in the event of a major disease outbreak, such as bird flu. There are currently
Speaking to journalists at the AAAS conference in Boston, lead researcher Dr Mike McGrew, of the University of Edinburgh’s Roslin Institute, which brought the world Dolly the sheep, said: “These chickensare a first step in saving and protecting rare poultry breeds from loss in order.
“What we wanted was to make a sterile chicken so what we can use stem cells from any breed of chicken and transplant them into this sterile female and be able to make eggs from that chicken.
“Where interested in chicken because that is most consumed animal on the planet and we want to protect all the different breeds of chickens that we have.
“You can take eggs from different breeds of hen and the mother hen will sit on the eggs and raise them themselves so that is not going to be a problem.”
According to the rare breeds survival trust, Britain has around 40 endangered breeds of chicken, including The Sultan, which was developed as an ornamental breed for the Sultan of Constantinople and was introduced to the UK in 1854, and the Arauca, which accidentally ended up on British shores following a shipwreck off the coast of the Hebrides.
The Scots Dumpy is one of the oldest chickens in Britain, with records dating back to Saxon times, although legends claim that when the Roman Army moved into Scotland, nearly 2,000 years ago, the Picts used the birds to as guards to warn of strangers approaching their camp.
The breed almost disappeared in the middle of the last century, when the breed went into severe decline.
Under the new project to create bank of stem cells, if a rare species did die out if could be brought back to life using a surrogate.
Richard Broad, a field officer for the Rare Breeds Survival Trust, said many rare breeds were facing extinction because they did not grow as fast as the broiler chicken, which is the most common meat producing bird and is ready to eat within a month.
“Consider the Dorking. If you were sitting around in England in Roman times that's the chicken you're eating, a traditional meat chicken,” he said.
“The problem is it doesn’t grow to the size it needs to be in 30 days, like a modern chicken. They’ve been selected for - at a cost to birds’ survivability and taste.”
But conservationists believe the project could create a ‘genetic ark’ which could help preserve the genetic profiles of rare breeds.
“Basically you can just have a gene bank of rare breeds in the freezer,” added Mr Broad.
Scientists used a genetic editing tool called Talen to delete a chicken gene called DDX4 which is crucial to bird fertility.
Hens with the genetic modification were unable to produce eggs but were otherwise healthy, the team found.
Reproductive stem cells, known as primordial germ cells, could then be implanted into the surrogates, who would go on to lay eggs of the rare breed. Although the team is only working on chickens at the moment, the technique could be used to conserve other endangered birds.
Dr Alison Van Eenennaam, who is also presenting work at the AAAS on the genetic modification of cows, said: “Hypothetically such hens could be complemented with primordial germ cells from other avian species, however whether such hens would be fertile and would be able to successfully produce viable offspring from other breeds remains to be shown.
“Such requirements might be expected to differ between species of different sizes and developmental rates. “
The study was published in the journal Development.