Becoming Human
The genetic architecture of and evolutionary constraints on the human pelvic form
Liaoyi Xu et al.
Science, 11 April 2025
Abstract:
Human pelvic evolution following the human-chimpanzee divergence is thought to result in an obstetrical dilemma, a mismatch between large infant brains and narrowed female birth canals, but empirical evidence has been equivocal. By using deep learning on 31,115 dual-energy x-ray absorptiometry scans from UK Biobank, we identified 180 loci associated with seven highly heritable pelvic phenotypes. Birth canal phenotypes showed sex-specific genetic architecture, aligning with reproductive function. Larger birth canals were linked to slower walking pace and reduced back pain but increased hip osteoarthritis risk, whereas narrower birth canals were associated with reduced pelvic floor disorder risk but increased obstructed labor risk. Lastly, genetic correlation between birth canal and head widths provides evidence of coevolution between the human pelvis and brain, partially mitigating the dilemma.
Hunter-gatherer sea voyages extended to remotest Mediterranean islands
Eleanor Scerri et al.
Nature, forthcoming
Abstract:
The Maltese archipelago is a small island chain that is among the most remote in the Mediterranean. Humans were not thought to have reached and inhabited such small and isolated islands until the regional shift to Neolithic lifeways, around 7.5 thousand years ago (ka). In the standard view, the limited resources and ecological vulnerabilities of small islands, coupled with the technological challenges of long-distance seafaring, meant that hunter-gatherers were either unable or unwilling to make these journeys. Here we describe chronological, archaeological, faunal and botanical data that support the presence of Holocene hunter-gatherers on the Maltese islands. At this time, Malta’s geographical configuration and sea levels approximated those of the present day, necessitating seafaring distances of around 100 km from Sicily, the closest landmass. Occupations began at around 8.5 ka and are likely to have lasted until around 7.5 ka. These hunter-gatherers exploited land animals, but were also able to take advantage of marine resources and avifauna, helping to sustain these groups on a small island. Our discoveries document the longest yet-known hunter-gatherer sea crossings in the Mediterranean, raising the possibility of unknown, precocious connections across the wider region.
Demographic interactions between the last hunter-gatherers and the first farmers
Alfredo Cortell-Nicolau et al.
Proceedings of the National Academy of Sciences, 8 April 2025
Abstract:
Demographic interaction processes play a pivotal role during episodes of cultural diffusion between different populations, particularly when these episodes can lead to competition for the same resources and geographic space. The diffusion of farming is one prototypical case within this broader scenario, where groups of incumbent hunter-gatherers occupied a space which would later be claimed by expanding farmers. In this work, we tackle such processes through a two-population mathematical model, where farmers and foragers compete and interact in the same geographic space. We present this work as a conceptual approach where, first, we assess the implications of our theoretical model and its general applicability and, second, we empirically test it on three case studies: Denmark, Eastern Iberia, and the island of Kyushu (Japan). While these regional case studies do not encompass the full range of processes observed in the interaction between migrant farmers and incumbent hunter-gatherers they provide reasonable variation to illustrate how our model can be fitted to a diverse range of empirical data and provide insights into these demographic processes. In particular, our theoretical model and case studies illustrate how endogenous interaction processes alone can explain the demographic fluctuations observed in the archaeological record during this transition, highlighting how these should be accounted for before invoking external forces as primary drivers.
Enamel–dentine junction morphology reveals population replacement and mobility in the late prehistoric Middle Nile Valley
Nicolas Martin et al.
Proceedings of the National Academy of Sciences, 15 April 2025
Abstract:
Transitions from foraging to food-production represent a worldwide turning point in recent human history. In the Middle Nile Valley this cultural shift occurred between the sixth and beginning of the fifth millennium BCE. Significant craniodental morphological differences remain inadequately tested by biometric analyses of ancestry and may reflect population origins or diet change between the last hunter-fisher-gatherers (Mesolithic) and first food-producers (Neolithic). Moreover, with no ancient DNA data for this region and very few morphological studies including large samples of Mesolithic individuals, the late prehistoric population history of the Nile Valley remains unclear. Here, we present enamel–dentine junction (EDJ) morphological analyses (based on X-ray microtomography) and biological affinities for 88 individuals spanning 14,000 y from Sudan and southern Egypt. Significant EDJ morphological differences between the last foragers and first food-producers suggest major biological discontinuity at the Neolithic transition. Nevertheless, the persistence of the earlier forager population in the Sudanese Eastern Sahara indicates settlement and population replacement mainly along the Nile. We also present biological evidence of interaction and mobility between these contemporaneous populations during the middle Holocene in the region. It supports the phylogenetic value of EDJ morphology for investigating population affinities at a microevolutionary scale. These results yield insights into the deep population history of the Nile Valley. They provide firm evidence for population replacement and migration toward the region at the onset of the Neolithic transition, attesting that these key changes were not solely triggered by cultural diffusion and diet change.
A male Denisovan mandible from Pleistocene Taiwan
Takumi Tsutaya et al.
Science, 10 April 2025, Pages 176-180
Abstract:
Denisovans are an extinct hominin group defined by ancient genomes of Middle to Late Pleistocene fossils from southern Siberia. Although genomic evidence suggests their widespread distribution throughout eastern Asia and possibly Oceania, so far only a few fossils from the Altai and Tibet are confidently identified molecularly as Denisovan. We identified a hominin mandible (Penghu 1) from Taiwan (10,000 to 70,000 years ago or 130,000 to 190,000 years ago) as belonging to a male Denisovan by applying ancient protein analysis. We retrieved 4241 amino acid residues and identified two Denisovan-specific variants. The increased fossil sample of Denisovans demonstrates their wider distribution, including warm and humid regions, as well as their shared distinct robust dentognathic traits that markedly contrast with their sister group, Neanderthals.
Quina lithic technology indicates diverse Late Pleistocene human dynamics in East Asia
Qi-Jun Ruan et al.
Proceedings of the National Academy of Sciences, 8 April 2025
Abstract:
The Late Pleistocene of Eurasia is key for understanding interactions between early modern humans and different types of archaic human groups. During this period, lithic technology shows more diversity and complexity, likely indicating flexible adaptative strategies. However, cultural variability as expressed by technological types remains vague in large parts of eastern Eurasia, like in China. Here, we report a complete Quina technological system identified from the study of the Longtan site in Southwest China. The site has been securely dated to ca. 60 to 50 thousand years ago (ka), with compelling evidence of core exploitation, production of large and thick flakes, shaping and maintenance of scrapers exhibiting the whole Quina concept, typical of contemporary European Middle Paleolithic technologies developed by Neanderthal groups adapted to climatic oscillations during Marine Isotope Stage (MIS) 4 and early MIS 3. The finding of a Quina lithic assemblage in China not only demonstrates the existence of a Middle Paleolithic technology in the region but also shows large-scale analogies with Neanderthal behaviors in western Europe. Longtan substantially extends the geographic distribution of this technical behavior in East Asia. Although its origin remains unclear, implications for Pleistocene hominin dispersal and adaptation to diverse ecological settings are considered. The Longtan lithic evidence also provides perspectives for understanding the cultural evolutionary situation before the large-scale arrivals of early modern humans in East Asia predating ~45 ka.