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"Dogs, like humans, were greatly affected during the colonization of the Americas by Europeans", says Sinc Laurent Frantz, a researcher at Oxford University and at the University of Oxford. 39, Queen Mary University London. After the settlers arrived, the dogs disappeared quickly and almost completely.
"This study shows that the history of humans is reflected in our domestic animals," says Larson
"The reason remains uncertain, but there are several possibilities: an infectious disease or a change of preference for European dogs in local communities", the researcher points out. Modern American breeds such as farmers or chihuahuas are in fact descendants of other Eurasian species introduced into the Americas between the fifteenth and twentieth centuries.
Until now, the mystery of the emergence of these dogs on the European continent also remained unknown. A new study, published in Science and led by the Frantz team, traced back the origin by genomic badysis of ancient DNA obtained from bone found in some North American tanks and compared to the DNA of modern and ancient dogs outside the United States. Siberian Ancestor
"We traced their origin to Eurasia and discovered the most likely date they were introduced to America" reveals the scientist. After sequencing 71 mitochondria and 7 nuclear genomes from old North American and Siberian dogs in the last 9,000 years, the experts concluded that American dogs had genetic signatures that looked like no other dog
. wolves from North America, but descended from a common ancestor probably native to Siberia and dispersed in the Americas with people arriving on the mainland 11,000 years ago, during the first human migrations of the Asia to America.
Remains of an American dog
"This study shows that human history is reflected in our domestic animals.People in Europe and America were genetically different, just like their dogs.And just like the indigenous peoples of the Americas have been displaced by European settlers, so can their dogs, "says Greger Larson, director of the Paleogenomics and Bioarchaeology Research Network (Palaeo-BARN) at the University of Oxford.
A tumor as the only legacy
At present, there is almost no genetic trace of these animals, which disappeared almost completely with the arrival of Europeans. have identified what could be the only surviving legacy of these canids: a transmissible venereal tumor.This is a bad cancer that spreads in dogs by the transfer of live cancer cells during mating which is currently distributed worldwide.
"The only survivor of the extinct dog line is a tumor that can spread among dogs as an infection" says Leathlobhair
"About 8,000 years ago, in America or more likely in Siberia, a dog contracted cancer that became contagious," he tells Sinc Frantz. This founder was genetically very close to those who followed humans during the first migrations to America more than 11,000 years ago " continues the researcher.
When these first dogs died, the Most living genome this missing line was found in this transmissible tumor. "In other words, the genome contained in this tumor recalls a lineage of extinct dogs that has been living in Siberia and America for thousands of years. years, "he says.
"It is incredible to think that the only survivor of a lineage of extinct dogs is a tumor that can spread among dogs as an infection", adds Máire Ní Leathlobhair, co – Author of the Department of Veterinary Medicine of the University of Cambridge. "Although the DNA of this cancer has mutated over the years, it remains essentially the DNA of this founding dog originated many thousands of years," he concludes.
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