Far northeastern Siberia was the gateway to the Americas for ancient humans; today it is home to diverse cultures whose members speak many languages. During the Late Pleistocene period [i.e. the Last Glacial Period (LGP), lasting from ~126,000 to ~11,700 years ago], this area of Siberia was connected to North America; the land/ice bridge formed a region known as Beringia. Hunter-gatherer populations seem to have ranged widely across Siberia and into Beringia, sustained by large animals including woolly mammoths. Authors [see two attached articles plus News’N’Views editorial] performed whole-genome sequencing (WGS) on 34 and 48 ancient peoples, respectively, derived from bones located in northeastern Siberia and northern North America.
It should be made clear that present-day Native Americans descended from at least four distinct streams of ancient migration from Asia. First, people related to present-day East Asians moved into North and South America by ~14,500 years ago; these are referred to as ‘First Peoples’.
Second, people with a higher degree of genetic relatedness to Australasians, termed ‘Population Y’, contributed distinct ancestry to Indigenous groups now living in the Amazon River Valley.
Third, a stream of ancestry related to Palaeo-Eskimos spread throughout the American Arctic occurred during only the past 5,000 years.
Fourth, a lineage called here ‘Neo-Eskimo’ spread with the Thule and related archaeological cultures throughout the Arctic region around 800 years ago; today they are present in the Yup’ik and Inuit groups.
For naming the Arctic meta-populations, authors used names of recognized language families: Na-Dene, Eskimo–Aleut, and Chukotko-Kamchatkan. [These terms were chosen because genetic and linguistic relationship patterns are highly congruent in this region.]
Authors [see first paper attached at left] analyzed 34 newly recovered ancient genomes that dated to between 31,000 and 600 years ago. During this period, there had been at least three major migration events: [a] an initial peopling by a previously unknown Palaeolithic population of ‘Ancient North Siberians’ — distantly related to early West Eurasian hunter-gatherers; [b] arrival of East Asian-related peoples, which gave rise to ‘Ancient Palaeo-Siberians’ who are closely related to contemporary communities from far-northeastern Siberia, as well as Native Americans; and [c] a Holocene migration of other East Asian-related peoples, who authors have named ‘Neo-Siberians’, and from whom many contemporary Siberians are descended. Each of these population expansions largely replaced the earlier inhabitants — ultimately generating a mosaic genetic make-up of contemporary peoples who inhabit a vast area across northern Eurasia and the Americas.
Authors [see middle paper attached] present genomic data for 48 ancient individuals from Chukotka, East Siberia, the Aleutian Islands, Alaska, and the Canadian Arctic. They compared these data with genomic data from present-day Alaskan Iñupiat and West Siberian populations. Using methods based on rare-allele and haplotype sharing [remember that ‘haplotype’ means ‘a DNA segment containing alleles (i.e. one copy of the two copies of each gene in our genomes) which tend to be inherited together’; another definition is ‘a combination of alleles, or a set of single nucleotide variants (SNVs), found on the same chromosome], authors show that Palaeo-Eskimo-related ancestry is ubiquitous among peoples who speak Na-Dene and Eskimo–Aleut languages. Authors developed a comprehensive model for the Holocene peopling events of Chukotka and North America [check out some of the beautiful diagrams and maps in attached papers], and they show that the Na-Dene-speaking peoples, people of the Aleutian Islands, and Yup’ik and Inuit across the Arctic region all share ancestry from a single Palaeo-Eskimo-related Siberian source. Wow.
DwN
Nature 13 June 2o19; 570: 182-188 and 236-240 & News’N’Views pp 170-172