Scientists seem to have gained some insight into the age old mystery of how ancient American dogs vanished mysteriously from the face of the earth, and it is not at all like how you would expect.
According to a new paper published in Science, researchers have found that ancient American were probably not native to the Americas, and the earliest dogs migrated from Asia with human populations. The genetic information gathered from the remains of 71 ancient dog fossils recovered from Siberia and America revealed that early American dogs had similarities with their Siberian counterparts and likely shared ancestors in common. This defies the popular notion that American dogs had evolved from North American wolves.
“When we compare our ancient dog DNA to all other known dog/wolf DNA, we find that the closest relatives are the Siberian dogs. This mirrors what we know about humans at the time and sites in Siberia have records of people using dogs then.”
As well as studying the mitochondrial DNA, researchers also sequenced the nuclear genome of seven of the ancient dogs, as reported by Gizmodo, leading them to conclude that ancient dogs which lived in huge populations all over the Americas did not survive the onslaught of the European colonizers from the 15th century onward.
As Anna Linderholm, an assistant professor of anthropology at Texas A&M University who did much of the genome sequencing said, humans are predisposed to bringing their dogs along with them, and Europeans also brought their dogs when they discovered the New World. Unfortunately, this, coupled with other reasons including the fact that America’s new settlers must have killed native dog populations, as well as their disinterest in breeding the original American dog populations, meant that the original American dogs slowly vanished completely from the Americas.
Researchers have still not been able to fully pinpoint the exact reasons for their disappearance, and it is something which may remain shrouded in mystery pending further research, but modern American dog populations have almost nothing in common with their descendants — except one, the canine transmissible venereal tumor (CTVT), a sexually transmitted form of cancer that has spread globally.
“The cancer genome we found was a real surprise,” Linderholm said.
“This is the biggest twist I have seen in any project I have done. It is amazing to think that these cancerous cells spread and that they still exist all over the world. So in a weird way, the ancient dogs of America live on through these cancerous cells.”
According to researchers, this form of cancer is found in dogs today inhabiting the Americas, and this is the only feature which connects them with ancient American dogs who migrated from Siberia and other parts of Asia.
“It’s quite incredible to think that possibly the only survivor of a lost dog lineage is a tumor that can spread between dogs as an infection,” Maire Ni Leathlobhair of Cambridge University told CBS News.
Scientists believe the dogs might have contracted this form of cancer much before Europeans set foot here, going as back as 8,000 years.