Joan Brenner Coltrain

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.

Climate and diet in fremont prehistory: Economic variability and abandonment of maize agriculture in the Great Salt Lake basin

Research reported here is based on the stable isotope (δ 13C,δ 15N) and radiocarbon chemistry of Fremont burials from wetlands lining the eastern shores of the Great Salt Lake (GSL). Bone collagen stable isotope signatures covary with reliance on maize and intake of animal protein, facilitating useful reconstructions of past diet. Among the GSL Fremont, economic strategies vary over time with an initial increase in reliance on maize (A.D. 400–850) followed by a period of marked economic diversity (A.D 850–1150) then a return to reliance on wild foods (after A.D. 1150). During the period of greatest economic diversity, male and female diets vary significantly and male diets are correlated with status differences evidenced by grave goods. There is also a clear temporal correlation between the rapid abandonment of maize agriculture and significant moisture anomalies in regional tree-ring chronologies and pollen profiles. These results are discussed in the context of recent arguments regarding economic diversity, social complexity, and the demise of the Fremont.

The stable-and radio-isotope chemistry of western basketmaker burials: implications for early puebloan diets and origins

The timing and degree of reliance on maize agriculture in the Four Corners region of the American Southwest has been a central issue in studies that examine the origins of Puebloan society. Both diffusionist (various, but see Wills 1995) and migrationist (Berry and Berry 1986; Matson 1991) models have been proposed to explain the processes responsible for the movement of maize (Zea mays) north into the Four Corners region. This paper reports bone collagen stable carbon and nitrogen isotope values with paired accelerator radiocarbon dates on a large collection of human remains from western Basketmaker II/III sites in Marsh Pass and other areas of northeastern Arizona, as well as data on a small number of Puebloan remains including Chacoan Great House burials. The results make clear that Basketmaker II people were heavily dependent on maize by 400 B.C. Moreover, their degree of dependence is similar to that of Pueblo II and III farmers of the Four Corners region. These findings and the apparent rapidity of maize dependence support a migrationist model for the origins of maize farming in the northern Southwest.

The first archaeological evidence for death by spearing in Australia

An Aboriginal man done to death on the dunes 4000 years ago was recently discovered during excavations beneath a bus shelter in Narrabeen on Sydneys northern beaches. The presence of backed microliths and the evidence for trauma in the bones showed that he had been killed with stone-tipped spears. Now we know how these backed points were used. A punishment ritual is implied by analogies with contact-period observations made in the eighteenth century AD.

Hrdlicka's aleutian population-replacement hypothesis : A radiometric evaluation

In a 1945 monograph, Hrdlika argued that, at 1,000 BP, PaleoAleut people on Umnak Island were replaced by NeoAleut groups moving west along the island chain. His argument was based on cranial measurements of skeletal remains from Chaluka Midden and mummified remains from Kagamil and Ship Rock burial caves. By the 1980s, researchers had concluded that the transition demonstrated by Hrdlika, from a high oblong to a lowvaulted wide face, was merely one example of a global trend in cranial morphology and therefore population replacement had not occurred. Calibrated accelerator radiocarbon dates on purified bone collagen from 80 individuals indicate that PaleoAleuts were the oldest population in the Aleutians, with a time depth of ca. 4,000 years, that Paleo and NeoAleuts were fully contemporary on Umnak Island after 1,000 BP, and that the former continued to bury their dead as inhumations long after the introduction of NeoAleut mummification practices. These results as well as features of the Aleut dietary, genetic, and material record suggest that the appearance of NeoAleut people represents an influx of closely related people characterized by greater social complexity and that social disparities that may have existed between Paleo and NeoAleuts were largely subsumed in the social and demographic upheaval following Russian contact.In a 1945 monograph, Hrdlika argued that, at 1,000 BP, PaleoAleut people on Umnak Island were replaced by NeoAleut groups moving west along the island chain. His argument was based on cranial measurements of skeletal remains from Chaluka Midden and mummified remains from Kagamil and Ship Rock burial caves. By the 1980s, researchers had concluded that the transition demonstrated by Hrdlika, from a high oblong to a lowvaulted wide face, was merely one example of a global trend in cranial morphology and therefore population replacement had not occurred. Calibrated accelerator radiocarbon dates on purified bone collagen from 80 individuals indicate that PaleoAleuts were the oldest population in the Aleutians, with a time depth of ca. 4,000 years, that Paleo and NeoAleuts were fully contemporary on Umnak Island after 1,000 BP, and that the former continued to bury their dead as inhumations long after the introduction of NeoAleut mummification practices. These results as well as features of the Aleut dietary, g...

Inferring Population Continuity Versus Replacement with aDNA: A Cautionary Tale from the Aleutian Islands

Abstract In The Aleutian and Commander Islands and Their Inhabitants (Philadelphia: Wistar Institute of Anatomy and Biology, 1945), Hrdlička proposed a population replacement event in the Aleutian Islands approximately 1,000 years ago based on a perceived temporal shift in cranial morphology. However, the archaeological record indicates cultural, and presumed population, continuity for more than 4,000 years. We use mtDNA haplogroup data in the series of prehistoric eastern Aleutian samples (n = 86) studied craniometrically by Hrdlička to test alternative hypotheses regarding population continuity or replacement in the region. This molecular characterization, in conjunction with direct dating of individual specimens, provided increased resolution for hypothesis testing. Results indicate an apparent shift in mtDNA haplogroup frequencies in the eastern Aleutians approximately 1,000 years ago, in concert with changes in mortuary practices and isotopic signatures reflecting resource acquisition strategies. The earliest Aleut populations were characterized by a high frequency of haplogroup A, as are most modern populations of the North American arctic. Later prehistoric peoples in the Aleutians were characterized by a high frequency of haplogroup D and a correspondingly lower frequency of haplogroup A, a pattern typified by modern Aleut populations.

Optimal foraging theory and niche-construction theory do not stand in opposition

In a recent paper, Zeder (1) outlines core archaeological questions in domestication research, highlighting the importance of defining the process, when it happened, and why it happened in various global contexts. Importantly, she emphasizes the utility of separating initial domestication from intensive agricultural practices, pointing out that often, origins of agriculture studies actually deal with initial domestication. Zeder’s explicit separation of these two economic behaviors, as well as identification of various markers that indicate initial domestication, makes this an extremely valuable contribution.

Alaska Peninsula Stable Isotope and Radioisotope Chemistry: A Study in Temporal and Adaptive Diversity

Purified bone collagen from a small suite of human remains recovered at three sites on the Alaska Peninsula (Port Moller, Brooks River, and Mink Island) were analyzed for stable carbon and nitrogen isotope chemistry and were accelerator radiocarbon dated. Because samples sizes were small and faunal isotope chemistry lacking, results should be considered preliminary. However, these data indicate that each locality was represented by a somewhat different suite of subsistence strategies and covered a distinct temporal span. Port Moller burials (n = 7) from the Hot Springs site date to a calibrated 2σ range of 3547–1388 BP. Although marine foods clearly made the greatest contribution to these diets, individuals were not as heavily reliant on high-trophic-level marine taxa as eastern Aleutian groups to the west, given their intake of salmon and evidence of caribou hunting. Brooks River burials (n = 9) expressed an inland foraging focus with significant reliance on caribou and spawning salmon and covered a calibrated 2σ range of 1484–381 BP. In contrast, individuals from Mink Island (n = 7), dating to cal. 666–292 BP, were heavily reliant on high-trophic-level marine prey similar to but not as enriched isotopically as the Aleut, perhaps a consequence of limited access to caribou and greater reliance on invertebrates. This pattern suggests that prehistoric economic strategies on the Alaska Peninsula were diverse, characterized by fine-tuned adaptations to local ecological settings, perhaps mediated by ethnic factors and territorial and social pressures. In a synthesis of prehistoric occupation in southwestern Alaska, Dumond (1987) proposed three subsistence and settlement adaptations that varied primarily with respect to their reliance on marine versus terrestrial resources. Results of a recent stableand radioisotope study with 23 human remains from three localities on the Alaska Peninsula show a similar pattern. Although site locations do not fully match Dumond’s regional designations, three relatively distinct subsistence patterns are expressed in the isotope chemistry of these remains. Variation in marine intake is accompanied by three distinct temporal patterns. In this paper I report stable isotope and accelerator radiocarbon data for these burials and address their implications. However, this work merely gesturesPurified bone collagen from a small suite of human remains recovered at three sites on the Alaska Peninsula (Port Moller, Brooks River, and Mink Island) were analyzed for stable carbon and nitrogen isotope chemistry and were accelerator radiocarbon dated. Because samples sizes were small and faunal isotope chemistry lacking, results should be considered preliminary. However, these data indicate that each locality was represented by a somewhat different suite of subsistence strategies and covered a distinct temporal span. Port Moller burials (n = 7) from the Hot Springs site date to a calibrated 2σ range of 3547–1388 BP. Although marine foods clearly made the greatest contribution to these diets, individuals were not as heavily reliant on high-trophic-level marine taxa as eastern Aleutian groups to the west, given their intake of salmon and evidence of caribou hunting. Brooks River burials (n = 9) expressed an inland foraging focus with significant reliance on caribou and spawning salmon and covered a calibrated 2σ range of 1484–381 BP. In contrast, individuals from Mink Island (n = 7), dating to cal. 666–292 BP, were heavily reliant on high-trophic-level marine prey similar to but not as enriched isotopically as the Aleut, perhaps a consequence of limited access to caribou and greater reliance on invertebrates. This pattern suggests that prehistoric economic strategies on the Alaska Peninsula were diverse, characterized by fine-tuned adaptations to local ecological settings, perhaps mediated by ethnic factors and territorial and social pressures.

REVISITING HOGUP CAVE, UTAH: INSIGHTS FROM NEW RADIOCARBON DATES AND STRATIGRAPHIC ANALYSIS

The remarkable finds from the trans-Holocene archaeological record excavated at Hogup Cave, Utah, helped define our understanding of Great Basin prehistory. However, many scholars doubt the integrity of the sites depositional sequence and resulting chronological interpretations. To resolve these concerns, we produce several Bayesian chronological models combining 14 new radiocarbon dates with the results of past dating efforts. We first present an examination of the excavation and previously derived dates, finding that several of the most anomalous dates can be accounted for by details in the excavations field notes. We then report our new dates and construct an initial Bayesian chronological model to serve as a framework for three increasingly complex models synthesizing old and new dates from the site. The best-supported model divides the sites stratigraphy into four occupational phases: Strata 1 through 7 (9790 to 6490 cal B.P.), Stratum 8 (5840 to 3330 cal B.P.), Strata 9 and 10 (2870 to 2760 cal B.P.), and Strata 11 through 16 (2610 to 360 cal B.P.). This result raises several questions to direct future research and dating efforts at Hogup Cave and serves as a model for reevaluating complex stratigraphic sequences in western North America and beyond. Los descubrimientos excepcionales del registro arqueológico trans-Holoceno excavado en Hogup Cave, Utah, han ayudado a definir nuestro entendimiento de la prehistoria de la Gran Cuenca. Sin embargo, muchos estudiosos dudan la integridad de la secuencia deposicional del yacimiento y, por consiguiente, la validez de las interpretaciones resultantes. Para resolver este problema, se produjeron varios modelos cronológicos bayesianos que combinan 14 nuevas fechas de radiocarbono con las fechas procedentes de trabajos anteriores. En primer lugar se presenta un análisis de la excavación y de las fechas obtenidas anteriormente, demostrando que varias de las fechas más anómalas son explicadas en las notas de excavación. Luego se reportan las nuevas fechas y se presenta un modelo cronológico bayesiano inicial que es utilizado como marco de referencia para producir tres modelos cada vez más complejos que sintetizan las fechas anteriores y las más recientes. El modelo más consistente divide la estratigrafía del yacimiento en cuatro etapas de ocupación: los niveles 1–7 (9790-6490 cal a.P.), el nivel 8 (5840-3330 cal a.P.), los niveles 9–10 (2870-2760 cal a.P.) y los niveles 11–16 (2610-360 cal a.P.). Este resultado genera varias preguntas para guiar las investigaciones futuras en Hogup Cave y sirve como modelo para reevaluar las secuencias estratigráficas complejas en el oeste de Norteamérica y otras regiones.