Dogs may have been domesticated independently in Asia and Europe from two separate wolf populations, according to a new study led by the University of Oxford.
Man’s best friend may have been domesticated from distinct wolf populations on either side of the Old World. Image credit: Pixel-mixer.
How wolves became man’s best friend has remained controversial, both in terms of the number of times dogs evolved, as well as just where this evolution occurred.
Several studies have concluded that dogs were probably domesticated just once, yet the scientific community continues to debate whether this occurred in China, Central Asia, or Europe.
The Oxford-led researchers have reconstructed the evolutionary history of dogs by first sequencing the genome of a 4,800-year-old dog from bone excavated at the Neolithic Passage Tomb of Newgrange, Ireland.
They also obtained mitochondrial DNA from 59 ancient European dogs living between 14,000 to 3,000 years ago and then compared them with the full genome sequences of more than 2,500 modern wolves and dogs of different breeds from Western Eurasia and East Asia.
The results of their analyses demonstrate a genetic separation between modern dog populations currently living in East Asia and Europe. This population split seems to have taken place after the earliest archaeological evidence for dogs in Europe.
The new genetic evidence also shows a population turnover in Europe that appears to have mostly replaced the earliest domestic dog population there, which supports the evidence that there was a later arrival of dogs from elsewhere.
Lastly, a review of the archaeological record shows that early dogs appear in both the East and West more than 12,000 years ago, but in Central Asia no earlier than 8,000 years ago.
“Our analyses revealed a deep split separating modern East Asian and Western Eurasian dogs,” the authors wrote in a paper published in the June 3 issue of the journal Science.
“Surprisingly, the date of this divergence (14,000 to 6,400 years ago) occurs commensurate with, or several millennia after, the first appearance of dogs in Europe and East Asia.”
“Additional analyses of ancient and modern mitochondrial DNA revealed a sharp discontinuity in haplotype frequencies in Europe.”
“Combined, these results suggest that dogs may have been domesticated independently in Eastern and Western Eurasia from distinct wolf populations. East Eurasian dogs were then possibly transported to Europe with people, where they partially replaced European Paleolithic dogs.”
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Laurent A. F. Frantz et al. 2016. Genomic and archaeological evidence suggest a dual origin of domestic dogs. Science, vol. 352, no. 6290, pp. 1228-1231; doi: 10.1126/science.aaf3161
