Understanding the origins of European domestic pigs
Ancient pig genes from the Near East were changed completely by hybridisation with European wild boar.
Over the last 10,000 years, as humans have spread across the globe, pigs have followed alongside and played a key part in the development of society. Along with cows and sheep, domestic pigs have allowed us to change from nomadic hunter-gatherers to settled farming communities.
But until now the detailed history of their domestication in Europe has been something of a mystery.
A team of curators, researchers and archaeologists have been able to study the genes of modern European domestic pigs and trace where they came from more accurately. Richard Sabin, a mammal expert at the Museum, was one of them.
He says, 'This study, which involves work from 100 authors around the world, uses extensive DNA samples from both living animals and museum research collections.
'The work includes material from more than 40 specimens in the Natural History Museum's collection. It highlights the importance of using natural history collections to help our understanding of how humans have shaped the natural world over millennia.'
Domestic pigs' arrival in Europe
The study, published in PNAS, found that the genes of ancient pigs almost completely changed following their introduction to Europe.
Pigs were first domesticated in the Near East, a region roughly corresponding to the modern Middle East.
Pigs are omnivores and are happy to eat plants, fungi, fruit, insects, crustaceans and small vertebrates. This flexibility and adaptability have made them successful at surviving in a variety of habitats and allowed them to thrive wherever humans have taken them.
Archaeological evidence suggests that domestic pigs arrived in Europe about 8,500 years ago with farmers from the Near East.
But, confusingly, the DNA of modern European pigs is derived from European wild boar and not Near Eastern animals. Researchers have often wondered whether that means pigs were also independently domesticated in Europe.
Historically it has been problematic to classify archaeological pig remains as wild, hybrid or domestic just by examining the shape of their skeletons.
Now, DNA analysis has shown that most Near Eastern ancestry in European domestic pigs disappeared around 3,000 years ago as a result of gradual interbreeding with European wild boar.
This is a problem that farmers still report today: wild boar often make their way into a herd of domestic pigs and mate with females, transferring their genes into the herd.
In the past this happened so often that modern domestic pigs in Europe only share up to 4% of their DNA with the Near Eastern wild boars.
Most importantly, the research suggests that pigs were not domesticated independently in Europe. Rather, herds that were allowed to roam the countryside interbred with wild boars. This could have happened accidentally and haphazardly, or could have been a deliberate decision by farmers seeking to improve their animals.
Pigs at the Museum
The Museum has been the centre of research into animal domestication for decades. Its extensive collection of skeletons is invaluable for studies such as this.
Richard explains, 'We have hundreds of pig skeletons in the collection, including examples of wild and domestic pigs from a large number of European countries, so we were able to provide genetic material from many of the areas of interest.
'The study of the appearance and spread of domestic animals is an important component of the study of natural history, because there is great value in understanding their origins. By doing this, we will better understand how humans have shaped the natural world.'