New evidence that ancient floods "rewrote" civilizations along the Yangtze River

A new study has shown that an increase in rainfall and associated floods 4,000 years ago in the Middle Yangtze Valley likely caused the collapse of the Shijiahe culture

Changes in temperature and water availability have long since played a significant role in the trajectory of human civilizations. A major climate event around 4,200 years ago (known as the “4.2 kyr event”), which coincides with the decline of major ancient societies, has attracted considerable scientific attention. In China's middle Yangtze River region, the once-flourishing Shijiahe culture collapsed during this period. The reasons behind the abandonment of the ancient Shijiahe city and the abrupt disruption of its cultural development have been widely debated. Now, a research team including Dr. Jin Liao. Dr. Christopher Day, Prof. Chaoyong Hu, Prof. Gideon Henderson, Prof. Yuhui Liu from the University of Oxford’s Department of Earth Sciences and from China University of Geosciences (Wuhan), has shown that this collapse was caused by widespread flooding in the Yangtze Valley. These findings were published in National Science Review.

By analysing a stalagmite from Heshang Cave in the middle Yangtze Valley, the research team were able to create a precisely dated "rainfall yearbook". Stalagmites grow as rainwater water drips from the roof of a cave, and the dissolved minerals within add new layers of calcium carbonate to these stalagmite cave features that rise up from the floor below. The team performed high-precision measurements on the chemical makeup of these layers to determine their age and the amount of rainfall at the time they formed. A total of 925 sample measurements were used to infer how much yearly rainfall the middle Yangtze Valley received over a thousand year period.

Their new reconstruction showed that the valley experienced three low-rainfall intervals (less than 700 mm of rain per year) which lasted between 40 and 150 years, and two high-rainfall intervals (more than 1,000 mm per year) which lasted 80 and 140 years respectively. Comparing this to archaeological data from the region revealed that these high-rainfall periods were associated with increased flooding, widespread wetland expansion, and a significant decline in population within the valley.

The area experienced a particularly large climate and cultural shift 3,950 years ago, which coincided with the start of the longest high-rainfall interval reconstructed by the research team. During this period, excess rainfall caused lakes across the Middle Yangtze valley to expand, low-lying areas to become waterlogged, and suitable land for settlement and farming to sharply diminish. The impact of this change was significant for the Shijiahe culture; a decline in the number of archaeological remains starting at this time indicates a pronounced drop in population which persisted for centuries. Evidence suggests that the post‑Shijiahe population abandoned their urban centre in the valley and dispersed into surrounding higher‑elevation regions.

This study offers valuable insights for addressing current and future environmental change. The analysis reveals that even the peak precipitation during the high-rainfall period associated with the collapse of the Shijiahe civilization was lower than some extreme rainfall events observed in the modern instrumental record. This not only reflects the limited adaptive capacity of ancient societies, but also highlights the critical importance of modern day water management infrastructure, agricultural innovations, and governance systems in mitigating climate risks and safeguarding food security. Effectively managing these climate-driven extremes will thus become an essential challenge for achieving sustainable societal development in a climate-changing world.

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Journal

National Science Review

DOI

10.1093/nsr/nwaf567 

 

Preferential mating between Neanderthal males and human females

 

• Most modern humans with non-African ancestry carry small amounts of Neanderthal DNA across much of their genome but have little-to-none on their X chromosomes.
• New research from Penn challenges an old assumption that the cause was natural selection and a weeding out of “toxic” Neanderthal genes.
• The researchers found that Neanderthals have more human DNA on their X chromosomes than elsewhere in their genomes.
• Because males and females pass on X chromosomes differently, this genetic pattern, they found, points to a strong sex bias: preferential mating between Neanderthal males and human females.
• Their findings reveal the role of social interactions in human evolution—rather than just biological survival—in sculpting the human genome, challenging the idea that our evolution was driven solely by survival of the fittest.

The human genome is a rich, complex record of migration, encounters, and inheritance written over thousands of millennia. In this month of love, amid the exchange of flowers and cards, genomic research by members of Sarah Tishkoff’s lab at the University of Pennsylvania are revisiting a particularly intimate chapter, suggesting that ancient mating patterns between modern humans and Neanderthals shaped why Neanderthal DNA is largely missing from the human X Chromosome.

“Along our X chromosomes, we have these missing swaths of Neanderthal DNA we call ‘Neanderthal deserts,’” says Alexander Platt, a senior research scientist in the Tishkoff Lab. “For years, we just assumed these deserts existed because certain Neanderthal genes were biologically ‘toxic’ to humans—as tends to be the case when species diverge—so we thought the genes may have caused health problems and were likely purged by natural selection.”

Now, Tishkoff and her team have discovered a more social explanation.

In a paper published in Science, their analysis of Neanderthal and modern human genomes suggests that long-standing mating preferences—rather than genetic incompatibility—shaped which Neanderthal DNA sequences persisted in modern humans and which were gradually lost. Their findings reveal the role social interactions in sculpting the human genome, challenging the idea that human evolution was driven solely by survival of the fittest.

“We found a pattern indicating a sex bias: gene flow occurred predominantly between Neanderthal males and anatomically modern human females,” says Platt, co-first author of the paper, resulting in the loss of Neanderthal DNA X chromosomes of modern humans.

“Roughly 600,000 years ago, the ancestors of anatomically modern humans and their closest-related species, the Neanderthals, diverged, forming two distinct groups, says Tishkoff, the David and Lyn Silfen University Professor in Genetics and Biology in the Perelman School of Medicine and School of Arts & Sciences. “Our ancestors evolved in Africa, while the ancestors of Neanderthals evolved in and adapted to life in Eurasia. But that separation was far from permanent.”

Over hundreds of millennia, she adds, human populations migrated into Neanderthal territories and back again, and when these groups met, they mated, swapping segments of DNA.

To determine whether Neanderthal X chromosomes contain alleles from humans, the team identified modern human DNA preserved in three Neanderthals—Altai, Chagyrskaya, and Vindija—and compared this dataset against one of diverse African genomes, a control group who had historically never encountered a Neanderthal.

“What we found was a striking imbalance,” says Daniel Harris, a research associate in the Tishkoff lab and co-first author. “While modern humans lack Neanderthal X chromosomes, Neanderthals had a 62% excess of modern human DNA on their X chromosomes compared to their other chromosomes.”

This mirrorlike reversal was their answer. If the two species were biologically incompatible, modern human DNA should have been missing from Neanderthal X chromosomes as well. But because the team found an abundance of human DNA in Neanderthal X chromosomes, they were able to rule out reproductive incompatibility or toxic gene interactions as the barrier.

The remaining explanation, the team argues, lies in sex-biased interbreeding.

Because females carry two X chromosomes and males carry only one, mating direction matters. If Neanderthal males partnered more often with modern human females, fewer Neanderthal X chromosomes would enter the human gene pool, and more human X chromosomes would enter Neanderthal populations.

Mathematical models confirmed that this bias could reproduce the observed genetic patterns. Other possibilities, such as sex-biased migration, could theoretically produce similar results—but only through complex, shifting scenarios that varied across time and geography.

“Mating preferences provided the simplest explanation,” Platt says.

With the “who” and “how” of these ancient trysts established, the team is now turning their attention to the “why,” investigating whether similar genetic comparisons—specifically the ratio of diversity between X chromosomes and autosomes—can reveal the gender dynamics of Neanderthal society, such as whether females stayed with their birth families while males migrated to new groups.

By mapping these ancient interactions, the lab hopes to further illuminate the complex social lives of human’s closest evolutionary cousins.

Sarah Tishkoff is the David and Lyn Silfen University Professor in Genetics and Biology, and a Penn Integrates Knowledge University Professor with appointments in the Department of Genetics and Department of Medicine in the Perelman School of Medicine and in Department of Biology in the School of Arts & Sciences at the University of Pennsylvania. 

Daniel Harris is a research associate in the Perelman School of Medicine at Penn. 

Alexander Platt is a senior research scientist in Penn’s Perelman School of Medicine.

This work was supported by the National Institutes of Health (Grants 1R35GM134957 and R01AR076241) and the American Diabetes Association (Grant 1-19-VSN-02).

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Journal

Science

DOI

10.1126/science.aea6774 

Ancient DNA reveals 7,700-year-old "north-south corridor" linking Lake Baikal and northern China

 

Genetic and archaeological links found 7,700 years ago, challenging previous timelines of trans-Eurasian interaction

Peer-Reviewed Publication

Science China Press

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image: 

This figure illustrates the prehistoric gene flow and cultural interaction within and around the Yan Mountains region (YMR). The YMR served as a crucial corridor connecting the agricultural Central Plains of North China (green shaded area) with the Mongolian Plateau (yellow shaded area). During the Early Neolithic, a genetic corridor between the Lake Baikal region and the YMR (blue-red gradient line) already existed prior to the widespread development of pastoralism/nomadism. From the Middle to Late Neolithic, the Yan Mountains became a significant hub for the convergence of agricultural and pastoral gene flows, with complex interactions between the YMR, the Yellow River region, and the West Liao River region (indicated by dashed arrows). The inset highlights the similar unique burial posture found in both the Lake Baikal region and the YMR (STM_EN site), archaeologically demonstrating the connection between these two regions.

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Credit: ©Science China Press

An international research team has uncovered a previously unknown "north-south corridor" of human interaction. This prehistoric link connected Early Neolithic populations from the Lake Baikal region of Siberia with those in the Yan Mountain Region (YMR) of northern China, thousands of years before the rise of pastoralism.

The study, published today in the journal Science Bulletin, challenges the long-held view that significant contact between the Eurasian Steppe and northern Chinese agricultural societies only began with the spread of pastoralism and metallurgy in the Bronze Age.

By analyzing 42 ancient genomes from three archaeological sites, dating from 7,700 to 4,300 years before present (BP), the researchers identified a key population that serves as a genetic bridge. These individuals, from the Early Neolithic Sitaimengguying (STM_EN) site in northern China (ca. 7,700-7,400 BP), carried a distinct genetic signature linked to populations from Lake Baikal, specifically descendants of a group known as Ancient Paleo-Siberians (APS).

“The Sitaimengguying population is the critical link,” said Yinqiu Cui, a corresponding author and professor at the School of Life Sciences, Jilin University. “Without their genomes, this prehistoric north-south connection would have remained invisible. They served as a crucial intermediary, preserving the genetic signal from the Baikal region and allowing us to trace this legacy into later populations in northern China.”

This genetic link is strongly supported by rare archaeological evidence. The STM_EN site features unique round-bottomed vessels, a style previously only found in the Lake Baikal region. Furthermore, the burial practice at STM_EN—with males placed in a lateral position with overlapping limbs—was also prevalent at Lake Baikal.

The study also provided a high-resolution genomic snapshot of the Yan Mountain Region, an agropastoral transition zone. The team found that later Late Neolithic individuals from the Jiangjialiang (JJL_LN) site (ca. 4,800-4,300 BP) were genetically heterogeneous. They were the product of an ongoing admixture between the local, northern STM_EN-related groups and southern farming populations migrating from the Yellow River region.

“The Yan Mountain Region was clearly a dynamic border zone, a true sphere of interaction,” said Choongwon Jeong, a corresponding author and associate professor at the School of Biological Sciences, Seoul National University. “We see not just the early north-south connection, but also a continuous north-south admixture later in time. This highlights the YMR's pivotal role in shaping the genetic landscape of northern East Asia.”

This research provides a new, fine-scaled picture of population history in East Asia. By using the Ancient Paleo-Siberian ancestry as a tracer , the team has demonstrated that long-distance connections were shaping human genetics and culture in this region far earlier than previously understood.

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Journal

Science Bulletin

DOI

10.1016/j.scib.2025.11.013 

Stone Age deceased dressed in spectacular feather and fur headgear

A new research technique provides a fresh vantage point to Stone Age burial outfits and their decorations

Peer-Reviewed Publication

University of Helsinki

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image: 

Artist’s impression of the Skateholm burial island. In the foreground is a boy whose grave contained a deer hair and possibly a fragment of a woodpecker feather

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Credit: Tom Björklund

A recently published research article examines the microscopic remains of the clothing and burial items dating back roughly 7,000 years.

The study focused on the Skateholm I and II cemeteries in Scania, southern Sweden, with a total of 87 graves. In archaeological excavations carried out in the 1980s, objects made of stone as well as animal bones, antlers and teeth were recovered from the grounds. Skateholm is one of the most significant Mesolithic Stone Age burial sites in northern Europe.

Importance of birds and feathers

The University of Helsinki’s ERC-funded Animals Make Identities project has developed a technique to distinguish fibres, hairs and feather fragments from soil samples taken from graves. It is based on water-assisted fibre separation. The current study is the first to apply the technique to this extent, with a total of 35 graves studied.

According to researcher and archaeologist Tuija Kirkinen, who oversaw the analyses in the study, the technique can be applied to any archaeological materials, not just graves.

Kirkinen specialises in microarchaeology and organic material culture, particularly fibres, hairs and textiles.

“The technique works well. Species-level identification of microscopic feather and hair fragments is difficult, and this aspect of the analysis method can still be developed further.”

“The study underlines the significance of birds and their feathers, and it produces fascinating new knowledge,“ says Professor Kristiina Mannermaa, who heads the overall project and contributed to the study.

Knowledge of Stone Age clothing increases

According to Kirkinen, information on Stone Age clothing is scarce, even though skeletal remains and objects made of bone can be preserved under optimal conditions also in Fennoscandia.

“In general, fur, plant fibres and other soft organic materials have been recovered only under specific conditions, such as in underwater sites or in glaciers. For example, the fur clothing of Ötzi, found in the Italian Alps near the Austrian border, had been preserved so well that it was possible to restore his outfit. With our method, it is possible to find microscopic fibres even in areas with poor preservation conditions.”

The study demonstrates that the skins of aquatic birds as well as the furs of mustelids, felines and other fur animals were used to clothe the deceased buried at Skateholm.

Footwear made of fur and feathers

The large mammals represented in the graves included a deer and a ruminant (the auroch or the European bison). Hawk or eagle feathers, owl feathers and the hairs of small fur animals found around heads indicate that many of the dead wore impressive headdresses.

Fur and feather remains were also found in graves that were previously considered empty, meaning that no objects were found to accompany the skeletons.

In one such grave, a white hair from the winter pelage of a stoat or a weasel, a brown feline hair and fragments of a bird feather were detected at the feet of a deceased woman over 60 years of age. This suggests that she was wearing multicoloured footwear made of fur, feathers or bird skin.

Read more

Kirkinen, T., Larsson, L. & Mannermaa, K. 2026. Waterbirds, mustelids and bast fibres – evidence of soft organic materials in the Late Mesolithic Skateholm I and II cemeteries, Sweden. Archaeological and Anthropological Sciences.

Bronze Age mines in Spain may explain the origin of Scandinavian Bronze

 

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One of the largest newly recorded mining areas, extending approximately 200 x 50 meters. The scale shows intensive and coordinated Bronze Age extraction.

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Credit: Johan Ling

The survey took place between 9 and 16 February in the area around Cabeza del Buey in the province of Badajoz. The work was carried out in collaboration with the Universidad de Sevilla and archaeologists from the Museo Arqueológico Provincial de Badajoz.

In total, six Bronze Age mining sites were documented, ranging from smaller extraction areas to more substantial mining environments. Particularly remarkable was one mine where approximately 80 grooved stone axes were discovered—tools used to crush and process ore.

The mines contain copper, lead, and silver—metals that were central to Bronze Age economies and long-distance trade networks.

The background to the survey lies in previous research within Maritime Encounters and several research/archaeology projects led by Professor Johan Ling at the university of Gothenburg. Through lead isotope and chemical analyses of Scandinavian Bronze Age artefacts, researchers have previously demonstrated that much of the metal likely originated in southwestern Spain.

“The newly discovered Bronze Age mines identified over the past ten years – both by other research teams and through the approximately 20 new mines documented by our research group between 2024 and 2026 – are transforming our understanding of how interconnected Europe was already 3,000 years ago. These discoveries demonstrate that metal extraction in southwestern Europe was far more extensive and organized than previously recognized, and they provide a concrete archaeological context for the chemical and isotopic analyses that point to long-distance connections during the Bronze Age“, says Johan Ling, Professor of Archaeology.

Facts/ The Extremadura Survey

• Location: Area around Cabeza del Buey, Province of Badajoz, Spain
• Dates: 9–16 February
• Project: Maritime Encounters
• Partners: Universidad de Sevilla and Museo Arqueológico Provincial de Badajoz
• Result: Six previously unregistered Bronze Age mines
• Notable find: Approximately 80 grooved stone axes used for ore processing
• Metals: Copper, lead, and silver

Ancient diets reveal surprising survival strategies in prehistoric Poland

 

Peer-Reviewed Publication

Uniwersytet Gdanski

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Skeleton of a Bronze Age woman discovered at Karczyn-Witowy – among the earliest known millet-eaters in northern Poland 

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Credit: Adriana Romanska (AMU)

An international team of archaeologists and scientists has reconstructed the diets of prehistoric communities from north-central Poland, shedding new light on how people adapted to changing environments and shifting social landscapes over three millennia between the Neolithic and the Bronze Age.

The researchers analysed human remains from 60 individuals, dated between around 4100 and 1230 BC. This long timespan encompassed key periods of Central European prehistory, including the arrival of groups with steppe ancestry from the East and the first widespread use of millet in the region. Archaeological traces of these societies are often scarce: their lightly built houses decayed quickly, graves contained few objects, and poor soil conditions preserved little organic material. Traditional archaeology has therefore offered only a partial picture of how they lived.

To overcome these gaps, the team combined archaeological and anthropological study with cutting-edge scientific techniques to study human remains, including radiocarbon dating, ancient DNA analysis, and stable isotope measurements of carbon and nitrogen. This interdisciplinary approach allowed them to date the remains, and reconstruct diets, farming practices and even aspects of social organisation that would otherwise remain invisible.

One of the most striking findings concerns the Corded Ware communities, who arrived in north-central Poland in the late Neolithic around 2800 BC. Contrary to expectations that they would prefer open grasslands, isotopic evidence shows that the earliest Corded Ware people herded their animals in forests or wet river valleys – marginal zones away from the fertile soils long cultivated by local farmers. After several centuries, their diet shifted and began to resemble that of their farming neighbours, perhaps by borrowing herding practices already established among local communities.

The second major discovery relates to the introduction of millet. Across Eurasia, broomcorn millet was rapidly adopted, quickly becoming a dietary staple. In north-central Poland, however, the analysis of the isotopic make-up of bone collagen from human bones tell a different story. From around 1200 BC, some communities relied heavily on millet, while others consumed little or none. Remarkably, these groups also buried their dead in different ways: some reintroduced the older tradition of communal tombs used over generations, while others practised unusual paired burials in elongated pits, with the deceased placed foot-to-foot. These differences suggest that food choices were not only practical but also closely tied to identity and group boundaries.

The results also point to subtle social inequalities. Variations in the nitrogen isotope make-up of bone collagen were used to reflect the position of individuals in the food web. Some of them – particularly in the Early Bronze Age – had greater access to animal protein than others, hinting at emerging hierarchies that are otherwise invisible in the modest grave goods of the region.

The findings also show that peripheral regions did not merely imitate the cultural centres of Central Europe, but could develop according to their own alternative principles. Exploring these dynamics reveals the creativity of prehistoric communities and their capacity to adapt to changing environmental and social conditions.

Paper: https://royalsocietypublishing.org/rsos/article/13/2/250986/480522/Isotopic-insights-into-long-term-socio-economic

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Journal

Royal Society Open Science

DOI

10.1098/rsos.250968