Comparing signals of natural selection between three Indigenous North American populations.

While many studies have highlighted human adaptations to diverse environments worldwide, genomic studies of natural selection in Indigenous populations in the Americas have been absent from this literature until very recently. Since humans first entered the Americas some 20,000 years ago, they have settled in many new environments across the continent. This diversity of environments has placed variable selective pressures on the populations living in each region, but the effects of these pressures have not been extensively studied to date.

Mitochondrial diversity of Iñupiat people from the Alaskan North Slope provides evidence for the origins of the Paleo- and Neo-Eskimo peoples.

Objectives: All modern Iñupiaq speakers share a common origin, the result of a recent (∼800 YBP) and rapid trans-Arctic migration by the Neo-Eskimo Thule, who replaced the previous Paleo-Eskimo inhabitants of the region. Reduced mitochondrial haplogroup diversity in the eastern Arctic supports the archaeological hypothesis that the migration occurred in an eastward direction. We tested the hypothesis that the Alaskan North Slope served as the origin of the Neo- and Paleo-Eskimo populations further east.

Comparative analysis of the human saliva microbiome from different climate zones: Alaska, Germany, and Africa.

Background: Although the importance of the human oral microbiome for health and disease is increasingly recognized, variation in the composition of the oral microbiome across different climates and geographic regions is largely unexplored.

Results: Here we analyze the saliva microbiome from native Alaskans (76 individuals from 4 populations), Germans (10 individuals from 1 population), and Africans (66 individuals from 3 populations) based on next-generation sequencing of partial 16S rRNA gene sequences. After quality filtering, a total of 67,916 analyzed sequences resulted in 5,592 OTUs (defined at ≥97% identity) and 123 genera.

Ancient DNA from the Schild site in Illinois: Implications for the Mississippian transition in the Lower Illinois River Valley.

Archaeologists have long debated whether rapid cultural change in the archaeological record is due to in situ developments, migration of a new group into the region, or the spread of new cultural practices into an area through existing social networks, with the local peoples adopting and adapting practices from elsewhere as they see fit (acculturation). Researchers have suggested each of these explanations for the major cultural transition that occurred at the beginning of the Mississippian period (AD 1050) across eastern North America. In this study, we used ancient DNA to test competing hypotheses of migration and acculturation for the culture change that occurred between the Late Woodland (AD 400-1050) and Mississippian (AD 1050-1500) periods in the Lower Illinois River Valley.

Ancient DNA perspectives on American colonization and population history.

Ancient DNA (aDNA) analyses have proven to be important tools in understanding human population dispersals, settlement patterns, interactions between prehistoric populations, and the development of regional population histories. Here, we review the published results of sixty-three human populations from throughout the Americas and compare the levels of diversity and geographic patterns of variation in the ancient samples with contemporary genetic variation in the Americas in order to investigate the evolution of the Native American gene pool over time. Our analysis of mitochondrial haplogroup frequencies and prehistoric population genetic diversity presents a complex evolutionary picture.

The human genetic history of the Americas: the final frontier.

The Americas, the last continents to be entered by modern humans, were colonized during the late Pleistocene via a land bridge across what is now the Bering strait. However, the timing and nature of the initial colonization events remain contentious. The Asian origin of the earliest Americans has been amply established by numerous classical marker studies of the mid-twentieth century.