A new study provides new evidence that the first dogs in North America virtually disappeared after the arrival of Europeans.
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The only surviving legacy seems to be a cancer that arose from the cells of a dog that lived more than 8,000 years ago and has since spread to other dogs worldwide, an international team reported on Thursday in the journal Science.
Researchers compared the genomes of old and modern American dogs. The results confirm that the first domesticated dogs in North America came with people from Asia across the same Bering land bridge, which was used by humans much earlier.
These dogs have thrived for thousands of years, but mostly disappeared after contact with Europeans.
Scientists do not know why they disappeared.
"I find it really surprising," says geneticist Elinor Karlsson of the University of Massachusetts Medical School in Worcester, who did not participate in the study.
"There were millions upon millions of dogs across the continent that died out after the arrival of Europeans, and the fact that we do not know anything about it is a big hole."
In an essay, the historical To fill in gaps, the researchers sequenced the genetic material of 71
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