Kate Britton

The genetic prehistory of the New World Arctic

Introduction Humans first peopled the North American Arctic (northern Alaska, Canada, and Greenland) around 6000 years ago, leaving behind a complex archaeological record that consisted of different cultural units and distinct ways of life, including the Early Paleo-Eskimos (Pre-Dorset/Saqqaq), the Late Paleo-Eskimos (Early Dorset, Middle Dorset, and Late Dorset), and the Thule cultures. Genetic origins of Paleo-Eskimos and Neo-Eskimos. All Paleo-Eskimos represent a single migration pulse from Siberia into the Americas, independent of the Neo-Eskimo Thule people (ancestors of modern-day Inuit) and the related extinct Sadlermiut population. The Siberian Birnirk people were likely cultural and genetic ancestors of modern-day Inuit. We also show ancient admixture between the Paleo- and Neo-Eskimo lineages, occurring at least 4000 years ago. Rationale We addressed the genetic origins and relationships of the various New World Arctic cultures to each other and to modern-day populations in the region. We obtained 26 genome-wide sequences and 169 mitochondrial DNA sequences from ancient human bone, teeth, and hair samples from Arctic Siberia, Alaska, Canada, and Greenland, and high-coverage genomes of two present-day Greenlandic Inuit, two Siberian Nivkhs, one Aleutian Islander, and two Athabascan Native Americans. Twenty-seven ancient samples were radiocarbon dated for accurate cultural assignment, of which 25 were corrected for marine reservoir effect to account for the dominant marine component in these individuals’ diets. Results Nuclear and mitochondrial DNA data unequivocally show that the Paleo-Eskimos are closer to each other than to any other present-day population. The Thule culture represents a distinct people that are genetic and cultural ancestors of modern-day Inuit. We additionally find the Siberian Birnirk culture (6th to 7th century CE) as likely cultural and genetic ancestors of the Thule. The extinct Sadlermiut people from the Hudson Bay region (15th to 19th century CE), considered to be Dorset remnants, are genetically closely related to Thule/Inuit, rather than the Paleo-Eskimos. Moreover, there is no evidence of matrilineal gene flow between Dorset or Thule groups with neighboring Norse (Vikings) populations settling in the Arctic around 1000 years ago. However, we do detect gene flow between the Paleo-Eskimo and Neo-Eskimo lineages, dating back to at least 4000 years. Conclusion Our study has a number of important implications: Paleo-Eskimos likely represent a single migration pulse into the Americas from Siberia, separate from the ones giving rise to the Inuit and other Native Americans, including Athabascan speakers. Paleo-Eskimos, despite showing cultural differences across time and space, constituted a single population displaying genetic continuity for more than 4000 years. On the contrary, the Thule people, ancestors of contemporary Inuit, represent a population replacement of the Paleo-Eskimos that occurred less than 700 years ago. The long-term genetic continuity of the Paleo-Eskimo gene pool and lack of evidence of Native American admixture suggest that the Saqqaq and Dorset people were largely living in genetic isolation after entering the New World. Thus, the Paleo-Eskimo technological innovations and changes through time, as evident from the archaeological record, seem to have occurred solely by movement of ideas within a single resident population. This suggests that cultural similarities and differences are not solid proxies for population movements and migrations into new and dramatically different environments, as is often assumed. Arctic genetics comes in from the cold Despite a well-characterized archaeological record, the genetics of the people who inhabit the Arctic have been unexplored. Raghavan et al. sequenced ancient and modern genomes of individuals from the North American Arctic (see the Perspective by Park). Analyses of these genomes indicate that the Arctic was colonized 6000 years ago by a migration separate from the one that gave rise to other Native American populations. Furthermore, the original paleo-inhabitants of the Arctic appear to have been completely replaced approximately 700 years ago. Science, this issue 10.1126/science.1255832; see also p. 1004 Early Arctic humans differed from both present-day Inuit and Native Americans. [Also see Perspective by Park] The New World Arctic, the last region of the Americas to be populated by humans, has a relatively well-researched archaeology, but an understanding of its genetic history is lacking. We present genome-wide sequence data from ancient and present-day humans from Greenland, Arctic Canada, Alaska, Aleutian Islands, and Siberia. We show that Paleo-Eskimos (~3000 BCE to 1300 CE) represent a migration pulse into the Americas independent of both Native American and Inuit expansions. Furthermore, the genetic continuity characterizing the Paleo-Eskimo period was interrupted by the arrival of a new population, representing the ancestors of present-day Inuit, with evidence of past gene flow between these lineages. Despite periodic abandonment of major Arctic regions, a single Paleo-Eskimo metapopulation likely survived in near-isolation for more than 4000 years, only to vanish around 700 years ago.

Strontium isotope evidence for migration in late Pleistocene Rangifer: Implications for Neanderthal hunting strategies at the Middle Palaeolithic site of Jonzac, France

In order to understand the behaviours and subsistence choices of Palaeolithic hunter-gatherers, it is essential to understand the behavioural ecology of their prey. Here, we present strontium isotope data from sequentially-sampled enamel from three reindeer (Rangifer tarandus ssp.) and a single bison (Bison cf. priscus) from the late Middle Palaeolithic site of Jonzac (Chez-Pinaud), France. The results are used to investigate the ranging and migratory behaviours of these important prey species. We found that the bison had isotope values most consistent with a local range, while the three reindeer had values indicating a seasonal migration pattern. Due to the similarity of the patterning of two of the three reindeer and in conjunction with zooarchaeological results, we suggest that they may have been from the same herd, were likely killed around the same point during their seasonal round and may therefore be the product of a single hunting event or a small number of successive hunting events. The isotope analyses complement the zooarchaeological data and have allowed greater insight into the palaeoecology of these species, the palaeoenvironment, and Neanderthal site use and hunting strategies.

Oxygen isotope analysis of human bone phosphate evidences weaning age in archaeological populations

Here we report bone phosphate oxygen (δ(18)Op) values from perinates/neonates and infants (<3.5 years; n = 32); children (4-12 years; n = 12); unsexed juveniles (16-18 years; n = 2); and adult bones (n = 17) from Wharram Percy, North Yorkshire, England, in order to explore the potential of this method to investigate patterns of past breastfeeding and weaning. In prior studies, δ(15)N and δ(13)C analyses of bone collagen have been utilized to explore weaning age in this large and well-studied assemblage, rendering this material highly appropriate for the testing and development of this alternative method targeting the inorganic phase of bone. Data produced reveal (18)O-enrichment in the youngest perinatal/neonatal and infant samples, and an association between age and bone δ(18)Op (and previously-published δ(15)N values), with high values in both these isotope systems likely due to breastfeeding. After the age of 2-3 years, δ(18)Op values are lower, and all children between the ages of 4 and 12, along with the vast majority of sub-adults and adults sampled (aged 16 to >50 years), have δ(18)Op values consistent with the consumption of local modern drinking water. The implications of this study for the reconstruction of weaning practices in archaeological populations are discussed, including variations observed with bone δ(15)Ncoll and δ(18)Op co-analysis and the influence of culturally-modified drinking water and seasonality. The use of this method to explore human mobility and palaeoclimatic conditions are also discussed with reference to the data presented.

Maritime adaptations and dietary variation in prehistoric Western Alaska: Stable isotope analysis of permafrost‐preserved human hair

The reconstruction of diet and subsistence strategies is integral in understanding early human colonizations and cultural adaptations, especially in the Arctic-one of the last areas of North America to be permanently inhabited. However, evidence for early subsistence practices in Western Alaska varies, particularly with regards to the emergence, importance, and intensity of sea mammal hunting. Here, we present stable carbon and nitrogen isotope data from permafrost-preserved human hair from two new prehistoric sites in Western Alaska, providing a direct measure of diet. The isotope evidence indicates a heavy reliance on sea mammal protein among the earlier Norton-period group (1,750 ± 40 cal BP), confirming that the complex hunting technologies required to intensively exploit these animals were most likely already in place in this region by at least the beginning of 1st millennium AD. In contrast, analysis of the more recent Thule-period hair samples (650 ± 40 cal BP; 570 ± 30 cal BP) reveals a more mixed diet, including terrestrial animal protein. Sequential isotope analysis of two longer human hair locks indicates seasonal differences in diet in a single Norton-period individual but demonstrates little dietary variation in a Thule-period individual. These analyses provide direct evidence for dietary differences among Alaskas early Eskimo groups and confirm the antiquity of specialized sea mammal hunting and procurement technologies. The results of this study have implications for our understanding of human adaptation to maritime and high-latitude environments, and the geographical and temporal complexity in early Arctic subsistence.

Specialized Processing of Aquatic Resources in Prehistoric Alaskan Pottery?: A Lipid-Residue Analysis of Ceramic Sherds from the Thule‐Period Site of Nunalleq, Alaska

Largely missing from the debate surrounding the use of pottery among arctic and subarctic hunter-gatherers are site-based biomolecular studies of vessel contents. This study used lipid-residue analysis to elucidate vessel function at Nunalleq (GDN-248), a late Thule-period coastal village site in the Yup’ik area of Western Alaska. In total, 31 pottery sherds and five soil samples were analyzed using gas chromatography and/or gas chromatography–mass spectrometry. The ubiquitous presence of aquatic biomarkers in all the pottery sherds suggests that pottery function at the site was directly linked to the use of aquatic resources. This indication of relatively specialized use of pottery at Nunalleq is particularly interesting when considered within the context of the site’s broader subsistence strategies, which included use of both aquatic and terrestrial resources. These findings appear to support a more general association between higher-latitude pottery traditions and the use of aquatic resources, though this topic requires further research.

A stable relationship: isotopes and bioarchaeology are in it for the long haul

Given their ubiquity in dietary reconstruction, it is fitting that the story of isotopes began with a conversation over dinner. Although coined in scientific literature by Frederick Soddy (1913), the word ‘isotope’ was first conceived by Margaret Todd, a medical doctor (also known as the novelist ‘Graham Travers’, and an all-round gender-stereotype-smasher of their age). In 1912, Soddy and Todd were attending a supper in Glasgow. When talk turned to work, Soddy described the then nameless concept of elements of different masses that occupy the same place in the periodic table. Todd suggested the term ‘isotope’, from the Greek isos (‘same’) + topos (‘place’), and the name stuck (Nicol 1957; Nagel 1982).

Neanderthal selective hunting of reindeer? The case study of Abri du Maras (south-eastern France)

Monospecific exploitation of reindeer by Neanderthals is a common behaviour in the Upper Pleistocene of Western Europe. However, reindeer-dominated assemblages have largely been reported from regions of northern Germany and south-western France, with few examples noted in south-eastern France, where faunal assemblages yield most of the time a variety of other large ungulates such as red deer, horse and diverse bovids. Here, we present multi-strand (bio- and eco-) archaeological datasets from the site of Abri du Maras (level 4.1), situated at the mouth of the Ardèche and Rhône rivers, a new example of a reindeer-dominated Neanderthal site in south-eastern France. Dated to the beginning of the MIS 3, the zooarchaeological assemblage is dominated by reindeer (88% of the NISP, representing 16 individuals) but also includes horse, bison, giant deer (Megaloceros giganteus), red deer, ibex and lagomorphs. The combination of zooarchaeological, cementochronological and tooth microwear analyses evidence a single species-dominated spectrum, with catastrophic mortality and repeated autumnal deaths. This integrated approach provides an extensive picture of human subsistence behaviour, pointing to short-term hunting episodes of reindeer herds in an exceptional context of a quasi-exclusive Neanderthal accumulation. The high number of individuals and selective butchery may correspond with a cooperative and planned mass hunting strategy. The multidisciplinary approach undertaken here also incorporating paleontological, charcoal, ecological and isotopic analyses places the archaeological and zooarchaeological data within a broader regional palaeoenvironmental framework, providing valuable landscape-contextual information. The zooarchaeological data suggest a subsistence behaviour different from other Neanderthal reindeer-dominated assemblages often connected with specialised butchery or hunting sites.