Pig Domestication and Human-Mediated Dispersal in Western Eurasia Revealed through Ancient DNA and Geometric Morphometrics
- May 23, 2013
- 4 min read
Archaeological evidence suggests that pigs were domesticated from wild boar as early as 13,000–12,700 BC in the Near East in the Tigris Basin being managed in the wild in a way similar to the way they are managed by some modern New Guineans. Remains of pigs have been dated to earlier than 11,400 BC in Cyprus that must have been introduced from the mainland, which suggests domestication in the adjacent mainland by then. There was also a separate domestication in China which took place about 8000 years ago.
DNA evidence from sub-fossil remains of teeth and jawbones of Neolithic pigs shows that the first domestic pigs in Europe had been brought from the Near East. This stimulated the domestication of local European wild boar resulting in a third domestication event with the Near Eastern genes dying out in European pig stock. Modern domesticated pigs have involved complex exchanges with European domesticated lines being exported in turn to the ancient Near East. Historical records indicate that Asian pigs were introduced into Europe during the 18th and early 19th centuries.
The adaptable nature and omnivorous diet of the wild boar allowed early humans to domesticate it readily. Pigs were mostly used for food, but early civilizations also used the pigs’ hides for shields, bones for tools and weapons, and bristles for brushes. In India, pigs have been domesticated for a long time mostly in Goa and some rural areas for pig toilets. Though ecologically logical as well as economical pig toilets are waning in popularity as use of septic tanks and/or sewerage system is increasing in rural areas.
Pigs were brought to southeastern North America from Europe by de Soto and other early Spanish explorers. Escaped pigs became feral and caused a great deal of disruption to Native Americans cultures who had no domesticated livestock. Domestic pigs have become feral in many other parts of the world (e.g. New Zealand and northern Queensland) and have caused substantial environmental damage. Human-induced hybrids of the European boar with the domestic pig that became feral are also very nocive to environment, and agriculture (among the 100 most damaging animal species), especially in southeastern South America from Uruguay to Brazil’s MS (C-O) and SP (SE), where they are known as javaporcos (from javali and porco, thus “boar-pigs”).
With around 1 billion individuals alive at any time, the domesticated pig is one of the most numerous large mammals on the planet.
Zooarcheological evidence suggests that pigs were domesticated in Southwest Asia ∼8,500 BC. They then spread across the Middle and Near East and westward into Europe alongside early agriculturalists. European pigs were either domesticated independently or more likely appeared so as a result of admixture between introduced pigs and European wild boar. As a result, European wild boar mtDNA lineages replaced Near Eastern/Anatolian mtDNA signatures in Europe and subsequently replaced indigenous domestic pig lineages in Anatolia. The specific details of these processes, however, remain unknown.
To address questions related to early pig domestication, dispersal, and turnover in the Near East, we analyzed ancient mitochondrial DNA and dental geometric morphometric variation in 393 ancient pig specimens representing 48 archeological sites (from the Pre-Pottery Neolithic to the Medieval period) from Armenia, Cyprus, Georgia, Iran, Syria, and Turkey.
Our results reveal the first genetic signatures of early domestic pigs in the Near Eastern Neolithic core zone. We also demonstrate that these early pigs differed genetically from those in western Anatolia that were introduced to Europe during the Neolithic expansion. In addition, we present a significantly more refined chronology for the introduction of European domestic pigs into Asia Minor that took place during the Bronze Age, at least 900 years earlier than previously detected.
By the 5th century AD, European signatures completely replaced the endemic lineages possibly coinciding with the widespread demographic and societal changes that occurred during the Anatolian Bronze and Iron Ages.
There was also a separate domestication in China which took place about 8000 years ago. An international team of researchers, led by Durham University (UK) and the China Agricultural University, in Beijing, say their findings suggest a difference between patterns of early domestication and movement of pigs in Europe and parts of East Asia.
The research, published April 19 in the Proceedings of the National Academy of Sciences USA, looked at the DNA sequences of more than 1,500 modern and 18 ancient pigs. According to author Dr Greger Larson, in the Department of Archaeology, at Durham University: “Previous studies of European domestic pigs demonstrated that the first pigs in Europe were imported from the Near East. Those first populations were then completely replaced by pigs descended from European wild boar.
“However, despite the occurrence of genetically distinct populations of wild boar throughout modern China, these populations have not been incorporated into domestic stocks.
“The earliest known Chinese domestic pigs have a direct connection with modern Chinese breeds, suggesting a long, unbroken history of pigs and people in this part of East Asia.”
The finding is part of a wider research project into pig domestication and early human migration in East Asia.
The study also uncovered multiple centres of pig domestication and a complex picture of human migration across East Asia.
After pigs were incorporated into domestic stocks in Southeast Asia, the animals then migrated with people south and east to New Guinea, eventually reaching the remote Pacific, including Hawai’i, Tahiti, and Fiji, the researchers said.
The DNA analysis also found that wild boar were probably domesticated in many places including India and peninsular Southeast Asia several thousand years ago.
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