Dogs are humans' best friend indeed -- our relationship with dogs goes way back to the ancients times where we first domesticated them. Now, a new study by the University at Buffalo has traced the clues of an ancient bone fragment to uncover how dogs came to the Americas and which route they used to enter this part of the world.
DNA from a bone fragment -- a femur piece -- found in Southeast Alaska belongs to a dog that lived there about 10,150 years ago, revealing new clues about the canine history.
The study, which will be published on Feb. 24 in the Proceedings of the Royal Society B, draws on the analysis of the dog's mitochondrial genome. The researchers concluded that the animal was related to a family of dogs whose evolutionary history diverged from that of Siberian dogs as early as 16,700 years ago.
This split corresponds to the times where humans may have been migrating into North America along a coastal route.
The researchers had set out to learn how Ice Age climatic changes impacted animals' survival in the region. The bone fragment was first thought to be from a bear, but when they studied the DNA, the researchers were quick to realize that it was from a dog.
"We now have genetic evidence from an ancient dog found along the Alaskan coast. Because dogs are a proxy for human occupation, our data help provide not only a timing but also a location for the entry of dogs and people into the Americas. Our study supports the theory that this migration occurred just as coastal glaciers retreated during the last Ice Age," said Charlotte Lindqvist, an evolutionary biologist and senior author of the study.
Before this study was conducted, the earliest American dog bones were found in the U.S. Midwest. However, instead of the inner continental passage, the first dog and human might have migrated through the Northwest Pacific coastal route to make their way into the Americas.