SummaryWe report genome-wide ancient DNA from 49 individuals forming four parallel time transects in Belize, Brazil, the Central Andes, and the Southern Cone, each dating to at least ∼9,000 years ago. The common ancestral population radiated rapidly from just one of the two early branches that contributed to Native Americans today. We document two previously unappreciated streams of gene flow between North and South America. One affected the Central Andes by ∼4,200 years ago, while the other explains an affinity between the oldest North American genome associated with the Clovis culture and the oldest Central and South Americans from Chile, Brazil, and Belize. However, this was not the primary source for later South Americans, as the other ancient individuals derive from lineages without specific affinity to the Clovis-associated genome, suggesting a population replacement that began at least 9,000 years ago and was followed by substantial population continuity in multiple regions.

Paleo-Eskimos were the first people to settle vast regions of the American Arctic around 5,000 years ago, and were subsequently joined and largely displaced around 1,000 years ago by ancestors of present-day Inuit and Yup’ik1–3. The genetic relationship between Paleo-Eskimos and Native American, Inuit, Yup’ik and Aleut populations remains uncertain4–7. Here we present new genomic data for 48 ancient individuals from Chukotka, East Siberia, the Aleutian Islands, Alaska, and the Canadian Arctic. We co-analyze these data with new data from present-day Alaskan Iñupiat and West Siberian populations and published genomes. Employing new methods based on rare allele and haplotype sharing as well as established methods4,8–10, we show that Paleo-Eskimo-related ancestry is ubiquitous among populations speaking Na-Dene and Eskimo-Aleut languages. We develop a comprehensive model for the Holocene peopling events of Chukotka and North America, and show that several key migrations connected to the origin of the Na-Dene peoples, the peopling of the Aleutian Islands, and the spread of Yup’ik and Inuit across the Arctic region are genetically linked to a single Siberian source related to Paleo-Eskimos.

European population history has been shaped by migrations of people, and their subsequent admixture. Recently, ancient DNA has brought new insights into European migration events linked to the advent of agriculture, and possibly to the spread of Indo-European languages. However, little is known about the ancient population history of north-eastern Europe, in particular about populations speaking Uralic languages, such as Finns and Saami. Here we analyse ancient genomic data from 11 individuals from Finland and north-western Russia. We show that the genetic makeup of northern Europe was shaped by migrations from Siberia that began at least 3500 years ago. This Siberian ancestry was subsequently admixed into many modern populations in the region, particularly into populations speaking Uralic languages today. Additionally, we show that ancestors of modern Saami inhabited a larger territory during the Iron Age, which adds to the historical and linguistic information about the population history of Finland.

Highlights d Genomic and isotopes data suggest an African origin for the three individuals d One 14X Treponema pallidum sub. pertenue genome was recovered d One 1,500X hepatitis B virus genome was recovered d Both pathogen genomes cluster together with present day pathogens from Africa