This article is about the genetic lineage associated with the peopling of the Americas. For the archaeogenetics of the USR population, seeUpward Sun River site § Archaeogenetics.
Figure 2. Schematic illustration of maternal (mtDNA) gene-flow in and out of Beringia (long chronology, single source model).
Eastern Beringia during the LGM and retreat of the ice sheets
The Ancient Beringian lineage is extinct, and is not found as a contribution to modern indigenous lineages inAlaska. The 2018 study suggests that the AB lineage was replaced by or absorbed in a back-migration of "North Native American" (NNA) to Alaska. The modernAthabaskan populations are derived from an admixture of this NNA back-migration and aPaleo-Siberian (Early Paleo-Eskimo) lineage before about 2,500 years ago.[5]
The discovery was made fromarchaeogenetic analyses on the remains oftwo female infants discovered in 2013 at theUpward Sun River site (USR).[1] The USR site is affiliated with theDenali Complex, a dispersed archaeological culture of the American Arctic. The genomic analysis of nuclear DNA of the older of the two infants (USR1) was done at theCentre for Geogenetics at theUniversity of Copenhagen'sNatural History Museum of Denmark. Results from the team's genetic analysis were published in January 2018 in the scientific journalNature. The analysis compared the infant's genomes with both ancient and contemporary genomes. The results suggested that the pre-"Ancestral Native American" lineage derived from the East Asian lineage after 36 kya, with gene flow until about 25 kya. During 25–20 kya, this lineage was later substantially mixed with theAncient North Eurasian lineage (~35%), who are described as the "result of a palaeolithic admixture" between ancient West Eurasians and ancientEast Eurasians,[6] to form the "Ancestral Native American" lineage by 20 kya. The "Ancient Beringian" (AB) lineage derived from ANA and persisted without significant admixture in Alaska until the time of USR1, some 8,000 years later. The lineage of otherPaleo-Indians diverged from AB at ca. 20–18 kya, and further divided into "North Native American" (NNA) and "South Native American" lineages between 17.5 kya and 14.6 kya, reflecting the dispersal associated with the earlypeopling of the Americas.[1][3][4]
^Moreno-Mayar et al. (2018), fig. 3;Supplementary Material[permanent dead link] p. 37. "While the population represented by USR1 most likely occupied interior Alaska at least until 11.5 kya 74 (the age of USR1), it is present-day Na-Dene-speakers who presently occupy the region. Coupled with the geographic distribution of the Na-Dene language family, results showing that USR1 does not carry the Asian-derived ancestry component indicate that such ancestry entered the Americas after 11.5 kya [...] Altogether, these results indicate that the admixture event that gave rise to most Na-Dene-speakers, between NNA and a Siberian population occurred well after 11.5 kya and at least prior to ~2.5 kya (the age of individual 302)."
