By Liz Seward
The first domesticated pigs in Europe were introduced from the Middle East by Stone Age farmers, a new study shows.
European domestic pigs eventually became a top export
The international research project examined DNA in the jawbones or teeth of modern and 7,000-year-old pigs.
The genetic investigation provides fresh insight into the immigration of ancient peoples and ideas.
The scientists tell the journal PNAS that the incoming farmers brought more than just ideas - they brought examples of domesticated livestock.
Agriculture is thought to have begun about 12,000 years ago, in the central and western parts of the Middle East, known as the Near East to archaeologists.
Between 6,800-4,000 BC, farming methods spread across Europe, but the question of how these methods spread has not been fully established.
The two competing theories are that farming spread through cultural exchange, possibly during trading or that people migrated to Europe bringing their expertise with them.
A previous study, in 2005, analysed modern pig DNA and showed that all modern pigs are descended from European wild boar. This led researchers to conclude that early Europeans domesticated pigs independently of other farming methods.
This new study, however, has discovered that the first domesticated pigs in Europe did have Near Eastern ancestry, indicating that farmers migrated to Europe, bringing their "package" of livestock and farming methods with them.
Domestic pigs of European wild boar ancestry appear soon afterwards.
Dr Keith Dobney, from Durham University, told BBC News: "By use of genetics, we've shown that the earliest domesticated pigs that moved into Europe were originally from the Near East.
"That means that people moved these animals from the Near East into Europe.
"And what happened after that, which is even more interesting, is it appears that once they were introduced, these domesticated pigs spurred or lit the blue touch-paper for people to domesticate the local indigenous wild boar.
"So, we have a secondary domestication which is happening in Europe soon afterwards."
The DNA records show that European domestic pigs became widespread throughout Europe, and that the Near Eastern pigs disappeared.
Dr Greger Larson, from Uppsala University, Sweden, performed the genetic analysis.
"The domestic pigs that were derived from the European wild boar must have been considered vastly superior to those originally from the Middle East, though at this point we have no idea why," he said.
"In fact, the European domestic pigs were so successful that over the next several thousand years, they spread across the continent and even back into the Middle East where they overtook the indigenous domestic pigs.
"For whatever reason, European pigs were the must-have farm animal."
Studies of cattle also show that modern European cows are partly descended from ancient wild Italian aurochs, disputing a previous claim that all present-day European breeds are descended from cattle domesticated in the Near East.