New research by Oxford University and Queen Mary University of London resolved the pig paradox. Archaeological evidence has shown that pigs were domesticated in the Middle East and as such modern pigs should resemble a Middle Eastern boar. They do not. Instead, the genetic signatures of modern European domestic pigs resemble a European wild boar.
Posted in Proceedings with the National Academy of Sciences, the study shows how it happened. Working with more than 100 colleagues, researchers from Oxford's School of Archeology sequenced the DNA signatures of over 2,000 ancient pigs, including the genomes of 63 archaeological pigs collected in the Middle East and Europe over the last 10,000 years.
The findings revealed that the first pigs that came to Europe with farmers 8,000 years ago had a clear genetic origin in the Middle East. However, over the next 3000 years, ancient domestic pigs hybridized with European boar to such an extent that they lost almost all of their Middle Eastern origin. A certain low level of Middle Eastern origin, however, potentially remained in the genome of modern European domestic pigs, which probably explains their characteristic black and black and white spotty colors. Higher levels of Middle Eastern origin were also maintained in the pig islands in the Mediterranean islands, probably because these populations experienced a relatively lower gene flow in European wild boars compared to pigs on the mainland.
Professor Greger Larson, director of the Palaeogenomics & Bio-Archeology Research Network (PalaeoBarn) at Oxford and senior author of the study, said: "Access to ancient genomes in such a large space and time has allowed us to see the slow motion of replacing the entire genome of domestic pigs. This suggests that the management of pigs in Europe over the millennia has been extensive and that although pigs maintained selection for some coat colors, domestic pigs interacted with the boar often enough to lose the boar's ancestor from which they were obtained. "
Dr. Laurent Frantz, lead author of the study at Queen Mary University of London, said: "We are all taught that the initial domestication process was a great change, but our data suggests that almost no human selection during the first 2,500 years of domestication of pigs was important in the development of modern European commercial pigs. "
Now that the team has developed a timeline of the genomic history of pigs in western Eurasia, the next step in research will be to accurately identify, in the genome of modern European domestic pigs, several genes that have retained their original Middle Eastern origin. This will allow us to assess whether the artificial selection used by the first farmers in the Fertile Crescent, more than 10,000 years ago, left any further legacy in modern pigs beyond the color of the coat.
Modern pigs have more wild boar genes than was thought
Laurent A. F. Frantz el al., "Ancient pigs show almost complete genomic rotation after their introduction into Europe" PNAS (2019). www.pnas.org/cgi/doi/10.1073/pnas.1901169116
Ancient pigs survived full genomic turnover after arriving in Europe (2019, August 12)
was recovered on August 12, 2019
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