Frédérique Valentin

The genetic history of Ice Age Europe

Modern humans arrived in Europe ~45,000 years ago, but little is known about their genetic composition before the start of farming ~8,500 years ago. We analyze genome-wide data from 51 Eurasians from ~45,000-7,000 years ago. Over this time, the proportion of Neanderthal DNA decreased from 3–6% to around 2%, consistent with natural selection against Neanderthal variants in modern humans. Whereas the earliest modern humans in Europe did not contribute substantially to present-day Europeans, all individuals between ~37,000 and ~14,000 years ago descended from a single founder population which forms part of the ancestry of present-day Europeans. A ~35,000 year old individual from northwest Europe represents an early branch of this founder population which was then displaced across a broad region, before reappearing in southwest Europe during the Ice Age ~19,000 years ago. During the major warming period after ~14,000 years ago, a new genetic component related to present-day Near Easterners appears in Europe. These results document how population turnover and migration have been recurring themes of European pre-history.

Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe

How modern humans dispersed into Eurasia and Australasia, including the number of separate expansions and their timings, is highly debated [1, 2]. Two categories of models are proposed for the dispersal of non-Africans: (1) single dispersal, i.e., a single major diffusion of modern humans across Eurasia and Australasia [3-5]; and (2) multiple dispersal, i.e., additional earlier population expansions that may have contributed to the genetic diversity of some present-day humans outside of Africa [6-9]. Many variants of these models focus largely on Asia and Australasia, neglecting human dispersal into Europe, thus explaining only a subset of the entire colonization process outside of Africa [3-5, 8, 9]. The genetic diversity of the first modern humans who spread into Europe during the Late Pleistocene and the impact of subsequent climatic events on their demography are largely unknown. Here we analyze 55 complete human mitochondrial genomes (mtDNAs) of hunter-gatherers spanning ∼35,000 years of European prehistory. We unexpectedly find mtDNA lineage M in individuals prior to the Last Glacial Maximum (LGM). This lineage is absent in contemporary Europeans, although it is found at high frequency in modern Asians, Australasians, and Native Americans. Dating the most recent common ancestor of each of the modern non-African mtDNA clades reveals their single, late, and rapid dispersal less than 55,000 years ago. Demographic modeling not only indicates an LGM genetic bottleneck, but also provides surprising evidence of a major population turnover in Europe around 14,500 years ago during the Late Glacial, a period of climatic instability at the end of the Pleistocene.

Genomic insights into the peopling of the Southwest Pacific

The appearance of people associated with the Lapita culture in the South Pacific around 3,000 years ago marked the beginning of the last major human dispersal to unpopulated lands. However, the relationship of these pioneers to the long-established Papuan people of the New Guinea region is unclear. Here we present genome-wide ancient DNA data from three individuals from Vanuatu (about 3,100–2,700 years before present) and one from Tonga (about 2,700–2,300 years before present), and analyse them with data from 778 present-day East Asians and Oceanians. Today, indigenous people of the South Pacific harbour a mixture of ancestry from Papuans and a population of East Asian origin that no longer exists in unmixed form, but is a match to the ancient individuals. Most analyses have interpreted the minimum of twenty-five per cent Papuan ancestry in the region today as evidence that the first humans to reach Remote Oceania, including Polynesia, were derived from population mixtures near New Guinea, before their further expansion into Remote Oceania. However, our finding that the ancient individuals had little to no Papuan ancestry implies that later human population movements spread Papuan ancestry through the South Pacific after the first peopling of the islands.

Lapita Diet in Remote Oceania: New Stable Isotope Evidence from the 3000-Year-Old Teouma Site, Efate Island, Vanuatu

Remote Oceania was colonized ca. 3000 BP by populations associated with the Lapita Cultural Complex, marking a major event in the prehistoric settlement of the Pacific Islands. Although over 250 Lapita sites have been found throughout the Western Pacific, human remains associated with Lapita period sites are rare. The site of Teouma, on Efate Island, Vanuatu has yielded the largest burial assemblage (n = 68 inhumations) of Lapita period humans ever discovered, providing a unique opportunity for assessing human adaptation to the environment in a colonizing population. Stable isotope ratios (δ13C, δ15N, δ34S) of human bone collagen from forty-nine Teouma adults were analyzed against a comprehensive dietary baseline to assess the paleodiet of some of Vanuatus earliest inhabitants. The isotopic dietary baseline included both modern plants and animals (n = 98) and prehistoric fauna from the site (n = 71). The human stable isotope data showed that dietary protein at Teouma included a mixture of reef fish and inshore organisms and a variety of higher trophic marine (e.g. marine turtle) and terrestrial animals (e.g. domestic animals and fruit bats). The domestic pigs and chickens at Teouma primarily ate food from a C3 terrestrial environment but their δ15N values indicated that they were eating foods from higher trophic levels than those of plants, such as insects or human fecal matter, suggesting that animal husbandry at the site may have included free range methods. The dietary interpretations for the humans suggest that broad-spectrum foraging and the consumption of domestic animals were the most important methods for procuring dietary protein at the site. Males displayed significantly higher δ15N values compared with females, possibly suggesting dietary differences associated with labor specialization or socio-cultural practices relating to food distribution.

Comportements alimentaires au Moyen Âge à Grenoble : application de la biogéochimie isotopique à la nécropole Saint-Laurent (XIIIe–XVe siècles, Isère, France)

Abstract Isotopic analysis of 13 C and 15 N of 47 bones from Saint-Laurent de Grenoble cemetery (Grenoble, Isere), from the end of medieval period (XIIIth–XVth centuries AD) allowed to define the food status of animals with regard to the humans and to discuss the variability amongst adults. Adults who died young and those with small stature may have had diets poor in animal protein. The consumption of animal proteins was more important in the XVth than in the XIVth century and could illustrate a typical urban food economy providing its population with a more diversified diet than in rural areas.

Lapita Burial Practices: Evidence for Complex Body and Bone Treatment at the Teouma Cemetery, Vanuatu, Southwest Pacific

ABSTRACT Excavation of the 3,000-year-old Lapita cemetery of Teouma (Efate, Central Vanuatu) has allowed the first detailed investigation of mortuary practices of these initial colonizers of the Vanuatu archipelago. Focusing on one component of funerary practice: the adult corpse and bone treatment of 25 mortuary contexts recovered at the site during excavations in 2004 and 2005, the present study reveals that beyond a complex procedure common for all the deceased, there is marked diversity of funerary behavior. Utilizing current knowledge and practice regarding the method of field anthropology or archaeothanatology, including the chronology of joint disarticulation sequences, we were able to establish the following practices: treatment of corpses by inhumation in a container—pit or wrappers—not immediately filled with sediment, followed by exhumation of the skull and other bones of the upper part of the skeleton, and secondary deposition of bones, including the cranium. The identified variations reflect particular attitudes toward human remains which might be connected to the social position of the deceased and/or individual choice.

Diet and Human Mobility from the Lapita to the Early Historic Period on Uripiv Island, Northeast Malakula, Vanuatu

Vanuatu was first settled ca. 3000 years ago by populations associated with the Lapita culture. Models of diet, subsistence practices, and human interaction for the Lapita and subsequent occupation periods have been developed mainly using the available archaeological and paleoenvironmental data. We test these models using stable (carbon, nitrogen, and sulfur) and radiogenic (strontium) isotopes to assess the diet and childhood residency of past communities that lived on the small (<1 km2) island of Uripiv, located off the northeast coast of Malakula, Vanuatu. The burials are from the initial Lapita occupation of the island (ca. 2800–2600 BP), the subsequent later Lapita (LL, ca. 2600–2500 BP) and post-Lapita (PL, ca. 2500–2000 BP) occupations, in addition to a late prehistoric/historic (LPH, ca. 300–150 BP) occupation period. The human stable isotope results indicate a progressively more terrestrial diet over time, which supports the archaeological model of an intensification of horticultural and arboricultural systems as local resources were depleted, populations grew, and cultural situations changed. Pig diets were similar and included marine foods during the Lapita and PL periods but were highly terrestrial during the LPH period. This dietary pattern indicates that there was little variation in animal husbandry methods during the first 800 years of prehistory; however, there was a subsequent change as animal diets became more controlled in the LPH period. After comparison with the local bioavailable 87Sr/86Sr baseline, all of the Lapita and LPH individuals appeared to be ‘local’, but three of the PL individuals were identified as “non-local.” We suggest that these “non-locals” moved to the island after infancy or childhood from one of the larger islands, supporting the model of a high level of regional interaction during the post-Lapita period.

Evidence for Social and Cultural Change in Central Vanuatu Between 3000 and 2000 BP: Comparing Funerary and Dietary Patterns of the First and Later Generations at Teouma, Efate

ABSTRACT In the southern Melanesian islands of Vanuatu, as in New Caledonia, Fiji, and West Polynesia, the archaeological record indicates significant shifts in aspects such as patterns of settlement and mobility, landscape use, and pottery production, some 500 years (2500 BP) after initial colonization. The relatively uniform Lapita Cultural Complex, the first manifestation of human activity on these islands, was transformed in each archipelago into various distinctive cultural entities. Using dietary (δ13C and δ15N values measured in collagen) and mortuary data recorded in 43 Lapita and seven immediately Post-Lapita adult burials from the site of Teouma (Efate, Vanuatu), we demonstrate that these medium-term, transformative processes also affected the economic component of the social system as well as its symbolic and religious structures. Evolutionary change adapting to changing local conditions is envisioned as the likely dominant factor influencing this cultural trajectory, while environmental/climatic change, secondary migration, and internal social changes unrelated to adaptive processes could have interacted to produce the recorded patterns.

Early Lapita skeletons from Vanuatu show Polynesian craniofacial shape: Implications for Remote Oceanic settlement and Lapita origins

Significance The question of the origin of Pacific Islanders has exercised scientists since the first explorers’ voyages of the 16th century. Physical resemblance between Polynesians and Asian populations was detected, but in between were the islands of Melanesia, inhabited largely by people of different phenotype. However, the Lapita culture bridged this geographical divide 3,000 y ago. Morphological studies of early Lapita colonists from Teouma, Vanuatu align them with present-day Polynesian and Asian populations, whereas skeletal remains of later generations show a more Melanesian phenotype predominating. We suggest that migration streams from already-inhabited parts of Melanesia dating from the late-Lapita phase ultimately dominated the original Polynesian phenotype in eastern Melanesia, but not in Polynesia, which became relatively isolated soon after initial settlement. With a cultural and linguistic origin in Island Southeast Asia the Lapita expansion is thought to have led ultimately to the Polynesian settlement of the east Polynesian region after a time of mixing/integration in north Melanesia and a nearly 2,000-y pause in West Polynesia. One of the major achievements of recent Lapita research in Vanuatu has been the discovery of the oldest cemetery found so far in the Pacific at Teouma on the south coast of Efate Island, opening up new prospects for the biological definition of the early settlers of the archipelago and of Remote Oceania in general. Using craniometric evidence from the skeletons in conjunction with archaeological data, we discuss here four debated issues: the Lapita–Asian connection, the degree of admixture, the Lapita–Polynesian connection, and the question of secondary population movement into Remote Oceania.

An Analysis of the Last 1000 Years Human Diet on Tutuila (American Samoa) Using Carbon and Nitrogen Stable Isotope Data

This paper reports the first set of isotopic data relating to human diet from the Samoan Archipelago. Carbon and nitrogen stable isotope data measured on bone collagen were used to assess dietary patterns of prehistoric communities on Tutuila Island, American Samoa. We examined 14 human bones from three sites dated to three distinct periods: ~1,000 years ago (N = 5); -500 years ago (N = 8) and -150 years ago (N = 1). The isotopie data suggest that the human diet on Tutuila over the last 1,000 years was composed mainly of terrestrial resources with some consumption of coastal reef products. These data suggest a possible dietary change over time, with a higher dependence on marine resources in the earlier period shifting to a more terrestrial diet in the later period. Several possibilities for this dietary shift are suggested including: change in community specialization; marine resource depression; disintensification of marine procurement; intensification of horticultural production; and cultural or social changes in resource allocation.