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The oldest dog remains ever found in the Americas are 10,150 years old and prove canines were with humans when the land was first colonised 6,000 years before.
Analysis of a chunk of dog femur, which was found in southern Alaska, reveals the animal was a descendant of Siberian dogs.
Scientists believe these ancient dogs accompanied the first humans to the Americas at the end of the last Ice Age when glaciers were in retreat.
The finding backs up the theory that people migrated into what is today Alaska from eastern Russia by following a route along the coast as the Bering Strait thawed.
Experts believe dogs were first domesticated in Eurasia between 20,000 and 30,000 years ago.
Scroll down for video © Provided by Daily MailAnalysis of a chunk of dog femur, which was found in southern Alaska, reveals the animal was a descendant of Siberian dogs and died 10,150 years ago
When people, along with their pet dogs, completed this treacherous journey around 16,500 years ago they became the first humans ever to settle in the Americas.
Their dogs then slowly adapted to the new climate and environment and formed their own lineage, which is genetically distinct from the Siberian ancestors.
It is this genetic difference which was detected in the bone fragment and adds credence to theory that humans first arrived in North America via the coast more than 16 millennia ago.
The findings corroborates a study published recently by Oxford academics.
Traces of carbon isotopes in the bone indicate the dog survived on a predominantly marine diet, eating fish, seals and whale meat.
Dr Charlotte Lindqvist, co-author of the study from the University at Buffalo, said: 'Our study supports the theory that [the first human migration into the Americas] occurred just as coastal glaciers retreated during the last Ice Age.
'Our early dog from Southeast Alaska supports the hypothesis that the first dog and human migration occurred through the Northwest Pacific coastal route instead of the central continental corridor, which is thought to have become viable only about 13,000 years ago.'
Researchers studied the mitochondrial DNA of the dog. Mitochondrial DNA is different to the regular DNA in the nucleus of all cells. © Provided by Daily MailWhen people, along with their pet dogs, colonised the Americas around 16,500 years ago they became the first humans ever to settle in the Americas. Their dogs then slowly adapted to the new climate and environment and formed their own lineage, which is genetically distinct from the Siberian ancestors.
© Provided by Daily MailPictured, Flavio Augusto da Silva Coelho, a University at Buffalo PhD student holds the tiny fragment of dog bone which was studied
Remains of a dog that 'lived alongside humans' up to 20,000 years ago are unearthed in Italy
Archaeologists in September unearthed what they believe could be the oldest ever remains of a domesticated pet dog.
It is thought the remains could be between 14,000 and 20,000 years old, spanning back to the very dawn of the special relationship between humans and canines.
While dogs are known as man's best friend and one of the most domesticated animals on Earth, the origin of this dynamic is still a relative mystery.
Researchers from the University of Siena in Italy hope their discovery can shed light on how dogs made the change from wild carnivores to loving companions.
It is smaller and found in a compartment found inside the cell called the mitochondria which is known as the powerhouse of the cell and creates energy.
Unlike normal DNA, it is not a combination of both mother and father as it is passed down maternally.
However, it was enough to date and track the ancestry of the hound.
Dr Lindqvis said: '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.'
Researchers were studying hundreds of bones which had been excavated years before when they stumbled upon the femur fragment.
They originally thought it belonged to a bear, but DNA tests proved it was of canine origin.
Flavio Coelho, lead author of the study, said: 'The fossil record of ancient dogs in the Americas is incomplete, so any new remains that are found provide important clues.
'Before our study, the earliest ancient American dog bones that had their DNA sequenced were found in the US Midwest.
The findings were published in the journal Proceedings of the Royal Society B.Read more