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Human origins in a southern African palaeo-wetland and first migrations
Eva Chan et al.
Nature, forthcoming
Abstract:
Anatomically modern humans originated in Africa around 200 thousand years ago (ka). Although some of the oldest skeletal remains suggest an eastern African origin, southern Africa is home to contemporary populations that represent the earliest branch of human genetic phylogeny. Here we generate, to our knowledge, the largest resource for the poorly represented and deepest-rooting maternal L0 mitochondrial DNA branch (198 new mitogenomes for a total of 1,217 mitogenomes) from contemporary southern Africans and show the geographical isolation of L0d1’2, L0k and L0g KhoeSan descendants south of the Zambezi river in Africa. By establishing mitogenomic timelines, frequencies and dispersals, we show that the L0 lineage emerged within the residual Makgadikgadi–Okavango palaeo-wetland of southern Africa, approximately 200 ka (95% confidence interval, 240–165 ka). Genetic divergence points to a sustained 70,000-year-long existence of the L0 lineage before an out-of-homeland northeast–southwest dispersal between 130 and 110 ka. Palaeo-climate proxy and model data suggest that increased humidity opened green corridors, first to the northeast then to the southwest. Subsequent drying of the homeland corresponds to a sustained effective population size (L0k), whereas wet–dry cycles and probable adaptation to marine foraging allowed the southwestern migrants to achieve population growth (L0d1’2), as supported by extensive south-coastal archaeological evidence. Taken together, we propose a southern African origin of anatomically modern humans with sustained homeland occupation before the first migrations of people that appear to have been driven by regional climate changes.
Boom and bust in Bronze Age Britain: Major copper production from the Great Orme mine and European trade, c. 1600–1400 BC
Alan Williams & Cécile Le Carlier de Veslud
Antiquity, October 2019, Pages 1178-1196
Abstract:
The Great Orme Bronze Age copper mine in Wales is one of Europe's largest, although its size has been attributed to a small-scale, seasonal labour force working for nearly a millennium. Here, the authors report the results of interdisciplinary research that provides evidence that Great Orme was the focus of Britain's first mining boom, c. 1600–1400 BC, probably involving a full-time mining community and the wide distribution of metalwork from Brittany to Sweden. This new interpretation suggests greater integration than previously suspected of Great Orme metal into the European Bronze Age trade/exchange networks, as well as more complex local and regional socio-economic interactions.
Middle Paleolithic complex technology and a Neandertal tar-backed tool from the Dutch North Sea
Marcel Niekus et al.
Proceedings of the National Academy of Sciences, 29 October 2019, Pages 22081-22087
Abstract:
We report the discovery of a 50,000-y-old birch tar-hafted flint tool found off the present-day coastline of The Netherlands. The production of adhesives and multicomponent tools is considered complex technology and has a prominent place in discussions about the evolution of human behavior. This find provides evidence on the technological capabilities of Neandertals and illuminates the currently debated conditions under which these technologies could be maintained. 14C-accelerator mass spectrometry dating and the geological provenance of the artifact firmly associates it with a host of Middle Paleolithic stone tools and a Neandertal fossil. The find was analyzed using pyrolysis-gas chromatography-mass spectrometry, X-ray micro-computed tomography, and optical light microscopy. The object is a piece of birch tar, encompassing one-third of a flint flake. This find is from northwestern Europe and complements a small set of well-dated and chemically identified adhesives from Middle Paleolithic/Middle Stone Age contexts. Together with data from experiments and other Middle Paleolithic adhesives, it demonstrates that Neandertals mastered complex adhesive production strategies and composite tool use at the northern edge of their range. Thus, a large population size is not a necessary condition for complex behavior and technology. The mitigation of ecological risk, as demonstrated by the challenging conditions during Marine Isotope Stage 4 and 3, provides a better explanation for the transmission and maintenance of technological complexity.
Evidence of ritual breakage of a ground stone tool at the Late Natufian site of Hilazon Tachtit cave (12,000 years ago)
Laure Dubreuil et al.
PLoS ONE, October 2019
Abstract:
Destruction of valuables is a common behavior in human history. Ethnographic data show the polysemic, but fundamentally symbolic, nature of this act. Yet, research aimed at exploring symbolic destruction in prehistoric societies has underlined the difficulties in establishing unambiguous evidence for such behaviour. We present here the analysis of a basalt tool fragment which provides evidence for intentional breakage associated with ritual activity 12,000 years ago. The tool fragment was part of a unique assemblage of grave goods deposited in a burial pit of a woman suggested to have been a shaman (Hilazon Tachtit cave, Southern Levant). The reconstruction of the artefact’s life history through morphological, 3D, use wear, residue and contextual analyses suggest that: 1) the fragment was initially part of a shallow bowl used for mixing ash or lime with water; 2) the bowl was subsequently intentionally broken through flaking along multiple axes; 3) The bowl was not used after its breakage but placed in a cache before the interment of the deceased, accompanied with other special items. The broken bowl fragment underlines the ritualistic nature of the act of breakage in the Natufian society. The research presented in this paper provides an important window into Natufian ritual behaviour during the critical period of transformation to agricultural communities. In addition, our results offer new insight into practices related to intentional destruction of valuables associated with death-related ceremonies at the end of the Palaeolithic.
Adaptive archaic introgression of copy number variants and the discovery of previously unknown human genes
PingHsun Hsieh et al.
Science, 18 October 2019
Abstract:
Copy number variants (CNVs) are subject to stronger selective pressure than single-nucleotide variants, but their roles in archaic introgression and adaptation have not been systematically investigated. We show that stratified CNVs are significantly associated with signatures of positive selection in Melanesians and provide evidence for adaptive introgression of large CNVs at chromosomes 16p11.2 and 8p21.3 from Denisovans and Neanderthals, respectively. Using long-read sequence data, we reconstruct the structure and complex evolutionary history of these polymorphisms and show that both encode positively selected genes absent from most human populations. Our results collectively suggest that large CNVs originating in archaic hominins and introgressed into modern humans have played an important role in local population adaptation and represent an insufficiently studied source of large-scale genetic variation.