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https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2010083118/-/DCSupplemental
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[Music]
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dogs were our earliest companions during
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the prehistoric era ancient DNA studies
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reveal the intertwined journey of humans
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to the Americas and their loyal canine
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friends offering a glimpse into the
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fascinating partnership studies indicate
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that dogs are closely linked to the
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movements of human groups over time and
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across different regions for example
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when farmers migr from West Asia to
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Europe a particular group of dogs with a
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specific mitochondrial Hao group
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accompanied them the first dogs in New
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Zealand arrived with Polynesians and in
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the North American Arctic dogs with a
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unique mitochondrial DNA signature
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joined paleo Inu groups around 5,000
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years ago later when Inuit groups moved
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into the same region about 1,000 years
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ago a new population of dogs with
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different DNA signatures appeared these
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connections between human migrations and
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specific dog lineages likely began soon
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after dogs were domesticated from
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Eurasian gy wolves however we're unsure
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about the exact time and location of
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this domestication process scientists
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are trying to uncover the origins of
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domestic dogs the first animals
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domesticated during the pleistocene
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epoch amidst environmental changes
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studies suggest the original wolf
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population that led to dogs is extinct
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dog domestication likely occurred in
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Eurasia despite using genetics and
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archaeological evidence the timeline and
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specifics of dog domestication are still
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debated identifying early domestic dogs
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from wolves is challenging as common
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markers like tooth crowding and skull
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size often don't provide clear
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distinctions disputes arise over claims
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of early domestic dogs at certain sites
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due to difficulties in differentiation
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from wolves the site of Bono Basel in
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Germany stands out as the earliest
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generally accepted remains of a domestic
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dog dating back to approximately 15,000
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years ago the distinct morphology and
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genetics of this young dog set it apart
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from local woles additional potential
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domestic dog remains have been suggested
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at various prehistoric sites including
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some in Siberia and the Americas which
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are still under
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investigation scientists have studied
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the DNA of many ancient and modern dogs
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the analysis of nuclear DNA shows that
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all dogs come from three main groups of
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ancestors one from Western Eurasia
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mostly in Europe India and Africa one
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from East Asia like dingos and one from
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the Arctic like huskys and ancient
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American dogs these lineages were
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established at least 11,000 years ago
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when looking at mitochondrial DNA most
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modern dogs fall into four main groups
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called Hao groups a b c and d the
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majority belong to a Hao group ancient
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DNA studies found a unique Hao group A2B
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in preon dogs in the America South of
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the Arctic but it has almost disappeared
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in modern dogs within A2B there are four
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subgroups while a 2b1 is found all
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across the Americas the others are more
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localized scientists use molecular clock
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analysis to estimate when these haa
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groups split the oldest split within haa
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group a between lineages a1b and A2 is
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estimated to be around
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22,800 years ago this suggests that dogs
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were domesticated several thousand years
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before they appeared in the
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archaeological record this early
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timeline suggests that dogs were likely
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domesticated by the time humans migrated
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into the Americas researchers have
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traced native American ancestry back to
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a population that diverged from an East
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Asian ancestor around 30,000 years ago
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around 24,000 years ago this population
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split into two groups ancient paleo
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saberians in Northeast Asia and the
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basil Native Americans at approximately
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24,000 years ago both groups received
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gene flow from ancient North Siberians
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during the last glacial maximum around
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23,000 to 19 th000 years ago the basil
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branch of Native Americans underwent a
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period of isolation in Northeast Asia
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known as the binan standstill lasting
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possibly 2400 to 9,000 Years Around
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21,000 years ago the basil Branch split
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into ancient beringians and ancestral
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Native Americans both populations
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entered Eastern beringia present day
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Alaska with the ancient Binion not
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showing genomic evidence south of Alaska
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after around 9,000 years ago the
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ancestral Native Americans Diversified
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around
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15,700 years ago into northern and
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southern branches the split between
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northern and southern branches occurred
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as the ancestral Native Americans moved
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south from Alaska suggesting a route
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along the Pacific coast rather than the
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interior ice free Corridor which wasn't
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yet suitable for human foragers the
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estimated time of this split aligns with
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archaeological evidence of people in the
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Americas around 15,000 years ago
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supporting the idea of a Pacific Coastal
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route it's important to note that the
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actual arrival date in the Americas
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remains unclear as archaeological
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evidence provides a minimum age and
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genetic estimates offer a maximum value
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once south of the ice sheets the
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northern Branch had a limited Geographic
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spread while the southern Branch
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radiated throughout the hemisphere
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diverging genetically around 14 ,000 100
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years ago the relationship between the
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migration of humans and dogs into the
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Americas during the late Poli to scene
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period is fascinating it suggests that
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dogs may have accompanied the first
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people entering the Americas and
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explores the timeline of their
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Divergence the Americas were settled by
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humans relatively late and it's possible
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that when people first arrived they had
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dogs with them dogs could have played a
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role in help humans quickly spread
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throughout the region comparing the
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timelines of dog and human populations
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researchers found key points of
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convergence the introduction of dogs in
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the Americas is estimated using
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mitochondrial data and it aligns with
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the timing of human population splits
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ancient American dogs excluding the
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Arctic belong to the same lineage
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suggesting they coales with a Siberian
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dog lineage around 16.4 th000 years ago
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this time frame coincides with the
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peopling of the Americas the evidence
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indicates that dogs likely cross the
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bingel land bridge during the pleased to
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scene reaching the Americas before later
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human migrations the split between major
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Native American lineages aligns with the
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Divergence of dog lineages suggesting
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they evolve together while both
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ancestral Native Americans and ancient
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beringian groups could have brought dogs
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into the Americas archaeological
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evidence hints that ancestral Native
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Americans might have been the first
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arriving before the distinctive ancient
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beringians this suggests a connection
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between the migration of people and dogs
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into the Americas during this
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period ancient DNA suggests that dog
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domestication likely began in Siberia
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during the late police to scene a period
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around 26,000 to 19,000 700 years ago
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this aligns with the time when humans
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and their genetically diverse virgin
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groups were present in Siberia and
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Western binia the evidence indicates
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that human populations in this region
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were small and lived in relative
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isolation the lack of significant gene
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flow among these groups and the absence
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of archaeological sites suggest limited
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interaction with communities outside
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Siberia as these populations
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specifically the ancestors of Native
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Americans crossed into the Americas they
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brought dogs with them how did ancestral
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Native Americans acquire dogs the
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researchers proposed that dogs were
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likely domesticated from a wolf
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population in Siberia or Western binia
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during the late place to scene before
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ancestral Native Americans migrated into
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the Americas among the various groups
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present in Siberia during the last
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glacial maximum researchers eliminate
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some possibilities and suggest that the
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ancient North Siberian Ians are the more
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likely population to have initiated the
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domestication process genomic analyses
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of ancestral Native American individuals
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at Siberian sites show evidence of gene
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flow into both ancient Native American
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and Western Eurasian
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lineages this suggests a mechanism for
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the transfer of dogs into different
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groups supporting their movement both
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East and West following domestication
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the researchers propos that climatic
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conditions during the last glacial
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maximum brought human and wolf
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populations into proximity within
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refugial areas leading to increased
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interactions Mutual Scavenging of kills
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or wolves drawn to human campsites may
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have initiated a shift in the
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relationship between humans and wolves
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eventually resulting in dog
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domestication the evolving relationship
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between humans and dogs has played a
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crucial role in their successful Global
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spread with more insights expected as
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archaeological and scientific techniques
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Advance thank you for watching
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