Pig study illuminates ancient human activity
Pigs were first domesticated from wild boars in the Near East and taken to Europe by early farmers, but a new genetic study shows that European farmers then domesticated local boars, which eventually supplanted the foreign animals.
Migrating farmers then completed the circle, taking the European animals to the Near East, where they supplanted the first domesticates, according to a report Monday in the Proceedings of the National Academy of Sciences. Today, descendants of those first Near Eastern pigs exist only in a few, isolated feral herds on islands including Cyprus and Corsica, France.
The findings provide support for the idea that the introduction of farming to Europe involved a migration of farmers from the Near East, taking their domestic plants, animals and distinctive pottery with them. Many researchers have argued that farming was brought to Europe through an exchange of culture that involved little physical movement, but these findings seem to make that scenario much less likely.
The pig study also shows clear evidence of two migration pathways from the Near East. Researchers have long debated which dominated; now it appears both were used.
“The truth lies in a much more complex, much more nuanced picture,” said archeologist Melinda A. Zeder of the Smithsonian National Museum of Natural History, who was not involved in the research. “This shows that people were able to evaluate new technologies and adapt them to their own use. It gives ancient people a lot more credit.”
Archeologists have established that agriculture began about 10,000 years ago in the Near East. It spread rapidly west into and across Europe over the next 4,000 years, arriving in Britain about 4000 BC.
Since no sheep or goats were indigenous to Europe, those were clearly brought to the continent after domestication elsewhere. Cows were indigenous, but a variety of evidence has shown that they were displaced by animals that were probably first domesticated in the Near East.
Pigs have a different history. Previous results by archeologist Greger Larson of Britain’s Durham University have shown that the animals were independently domesticated at as many as nine sites around the world. Their relatively small size and portability enabled humans to take them on migrations, making the animals an excellent proxy for tracing human movements.
In the current study, Larson and his colleagues studied mitochondrial DNA from 323 modern and 221 ancient pig specimens.
They concluded that the earliest domesticated pigs were bred in the Near East and then moved west with migrating humans. By 4000 BC, the Near Eastern pigs had reached the Paris area.
The team identified two genetic signatures for the imported pigs: one associated with those that migrated through the Danube River basin in the heart of Europe, the other with pigs brought in by people who migrated along the Mediterranean coast before swinging north.
Archeologists had previously found different sets of cultural artifacts associated with these two migration routes, such as different types of pottery.
By the time the Near Eastern pigs got to Paris, the first pigs with DNA of European origin began showing up, Larson said. “European wild boar were definitely being domesticated, a process kick-started by the pigs that were brought in,” he said.
Within 500 years of the first locally domesticated pigs’ appearance, virtually all traces of the Near Eastern pigs disappeared.
“We don’t know why pigs from European wild boar were considered so superior to the original pigs from the Near East,” he said. Perhaps they were larger or meatier or had better resistance to cold weather. “But ancient farmers from France to Armenia seemed to love them.”
By 700 to 600 BC, the European pigs had spread to the Near East, where they supplanted the local species. “We never would have guessed that from looking at the modern data alone,” Larson said.
The team has not yet looked at pig lineages from Asia, but Larson said he was eager to do so. “We know the pigs were taken as far east as Armenia. Do they get taken along the Silk Road [to China]?”