page_title: Beringia
section_title: Human habitation
hierarchical_section_title: Beringia / Human habitation
caption_attribution_description: English: Map of gene flow in and out of Beringia, according to human mitochondrial DNA haplogroups. Colors of the arrows correspond to approximate timing of the events and are decoded in the colored time bar. The initial peopling of Beringia (the region depicted in light yellow) was followed by a standstill after which the ancestors of the Native Americans spread swiftly all over the New World while some of the Beringian maternal lineages (C1a) spread westwards. More recent genetic exchange (shown in green) is manifested by back-migration of A2a into Siberia and the spread of D2a into north-eastern America that post-dated the initial peopling of the New World.
context_page_description: Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72 degrees north latitude in the Chukchi Sea; and on the south by the tip of the Kamchatka Peninsula. It includes the Chukchi Sea, the Bering Sea, the Bering Strait, the Chukchi and Kamchatka Peninsulas in Russia as well as Alaska in the United States.
  The area includes land lying on the North American Plate and Siberian land east of the Chersky Range. Historically, it formed a land bridge that was up to 1,000 kilometres wide at its greatest extent and which covered an area as large as British Columbia and Alberta together, totaling approximately 1,600,000 square kilometres. Today, the only land that is visible from the central part of the Bering land bridge are the Diomede Islands, the Pribilof Islands of St. Paul and St. George, St. Lawrence Island, and King Island.
  The term Beringia was coined by the Swedish botanist Eric Hultén in 1937. During the ice ages, Beringia, like most of Siberia and all of North and Northeast China, was not glaciated because snowfall was very light.
context_section_description: The Bering land bridge is a postulated route of human migration to the Americas from Asia about 20,000 years ago.  An open corridor through the ice-covered North American Arctic was too barren to support human migrations before around 12,600 BP. A study has indicated that the genetic imprints of only 70 of all the individuals who settled and traveled the land bridge into North America are visible in modern descendants. This genetic bottleneck finding is an example of the founder effect and does not imply that only 70 individuals crossed into North America at the time; rather, the genetic material of these individuals became amplified in North America following isolation from other Asian populations.
  Seagoing coastal settlers may also have crossed much earlier, but there is no scientific consensus on this point, and the coastal sites that would offer further information now lie submerged in up to a hundred metres of water offshore. Land animals migrated through Beringia as well, introducing to North America species that had evolved in Asia, like mammals such as proboscideans and American lions, which evolved into now-extinct endemic North American species. Meanwhile, equids and camelids that had evolved in North America (and later became extinct there) migrated into Asia as well at this time.
  A 2007 analysis of mtDNA found evidence that a human population lived in genetic isolation on the exposed Beringian landmass during the Last Glacial Maximum for approximately 5,000 years. This population is often referred to as the Beringian Standstill population. A number of other studies, relying on more extensive genomic data, have come to the same conclusion. Genetic and linguistic data demonstrate that at the end of the Last Glacial Maximum, as sea levels rose, some members of the Beringian Standstill Population migrated back into eastern Asia while others migrated into the Western Hemisphere, where they became the ancestors of the indigenous people of the Western Hemisphere. Environmental selection on this Beringian Standstilll Population has been suggested for genetic variation in the Fatty Acid Desaturase gene cluster and the ectodysplasin A receptor gene. Using Y Chromosome data Pinotti et al. have estimated the Beringian Standstill to be less than 4600 years and taking place between 19.5 kya and 15 kya.
caption: Genetic settlement of Beringia
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