Tuesday, November 18, 2025

Medieval communities boosted biodiversity around Lake Constance

 

Peer-Reviewed Publication

Max Planck Institute of Geoanthropology

Abbey archives 

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Charter from the Abbey Archives of St. Gall. Dated March 9th, 736. Describes the donation of property in Eigeltingen and Neuhausen, near Lake Constance. Archived documents like this reveal the social, economic, and agricultural practices prevailing in the Lake Constance region during the early medieval period.

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Credit: St. Gallen, Stiftsarchiv, IV 345 (Private charter)

One of the major realizations of the Anthropocene era has been the importance of biodiversity for the functioning of the earth system, as well as for human societies. Recent trends show that human activities are driving biodiversity loss around the globe, but previous research has also shown an increase in biodiversity in Holocene Europe, showing that human societies can in fact support the health and resilience of their environments. The cultural phenomena that accompanied the increase in biodiversity, however, are less understood.

Now, a new study published in the Proceedings of the National Academy of Sciences integrates data from interdisciplinary datasets to examine the drivers of biodiversity change around Lake Constance in southwest Germany, then part of the Carolingian Empire. Researchers found a significant, sustained increase in plant diversity starting around 500 CE, culminating in a 4000-year “plant diversity optimum” around1000 CE. This increase, data shows, was driven by cultural innovations in agriculture, land management and trade in the formative period of medieval Europe.

“Our findings document a success story in human-environment interactions,” says Adam Izdebski of the Max Planck Institute of Geoanthropology. “Human communities can support biodiverse landscapes, and have done so for long periods of time in the past.”

“This study offers lessons for policy makers and conservationists,” adds Adam Spitzig of Stanford University. “Our data suggest that High Nature Value (HNV) farming systems and intermediate-disturbance, agro-ecological mosaics can effectively enhance plant diversity while simultaneously sustaining food production.”

To reach these findings, the researchers used palaeoecological and historical datasets from the Lake Constance region, a uniquely well-documented area. Analysis of fossil pollen from six sediment cores, combined with archaeobotanical evidence from hundreds of sites, allowed researchers to reconstruct the changes in plant diversity over the past 4000 years. By combining this data with historical documents from regional archives, including the Abbey Archives of St. Gall, they could uncover the agricultural, trade, and land management practices that enabled the increase in plant diversity.

As society progresses into the Anthropocene, the human era, stories of positive human-earth system interactions are increasingly important, reminding us that our societies can support biodiversity and healthy landscapes too. The researchers hope that future studies will continue to integrate long-term biodiversity estimates with detailed cultural contextualization, so that policy makers can implement the most effective biodiversity management policies.

The woman and the goose: a 12,000-year-old glimpse into prehistoric belief



A 12,000-year-old clay figurine unearthed in northern Israel, depicting a woman and a goose, is the earliest known human-animal interaction figurine. Found at the Late Natufian site of Nahal Ein Gev II, the piece predates the Neolithic and signals a turning point in artistic and spiritual expression. Combining naturalism, light manipulation, and symbolic imagination, it reveals how early communities used art to explore the relationship between humans and the natural world.

Link to pictures: https://drive.google.com/drive/folders/1nwEejOk2uaRGxAQN3yGCTMxhroZg6f0Z?usp=sharing

At a prehistoric village overlooking the Sea of Galilee, archaeologists led by Dr. Laurent Davin have uncovered a clay figurine unlike any found before. The 12,000-year-old artifact, depicting a woman and a goose in what appears to be a mythological or ritual scene, offers a rare window into the symbolic and spiritual world of early sedentary peoples in Southwest Asia.

Discovered at the site of Nahal Ein Gev II (NEG II), a project led by Prof. Leore Grosman of the Institute of Archaeology at the Hebrew University of Jerusalem, with Prof. Natalie Munro, they describe the find as the earliest known figurine showing human and animal interaction and the first naturalistic depiction of a woman in the region. The study, recently published in PNAS, combines advanced analytical techniques to reconstruct both the artifact’s composition and its cultural significance.

The Find: A Figurine of Clay and Light

The figurine, only 3.7 cm tall, was modeled from local clay and heated at about 400°C, suggesting deliberate control of early pyrotechnology. Microscopic and chemical analyses revealed red pigment residues (ocher) on both woman and goose, along with a preserved fingerprint likely left by the young adult or adult female artisan. The sculptor used light and shadow to create depth and perspective, foreshadowing artistic innovations that would not fully flourish until the Neolithic.

Depicting a woman crouched beneath a goose perched on her back, the scene suggests more than a simple act of daily life. The goose, common in the Natufian diet but also imbued with symbolic value, appears alive rather than hunted. Researchers interpret the composition as an imagined or mythological encounter consistent with animistic beliefs, a worldview that saw humans and animals as spiritually interconnected.

Context and Meaning

The figurine was found in the fill of a semicircular stone structure containing burials and ceremonial deposits, part of the Late Natufian settlement at Nahal Ein Gev II dated to approximately 12,000 years ago. The Natufian culture, spanning roughly 15,000 to 11,500 years ago, marks humanity’s transition from nomadic foragers to settled communities. The discovery reveals that long before agriculture, these early villagers were already experimenting with narrative art, symbolic expression, and clay modeling techniques.

Faunal remains from the site reinforce the connection between geese and ritual life. The birds’ feathers were used for decoration, and certain bones were fashioned into ornaments. The artistic focus on a goose and a woman, the researchers argue, points to an early mythic imagination, a symbolic vocabulary that later blossomed in Neolithic cults and figurative traditions across Southwest Asia.

A Glimpse into the Origins of Belief

"This discovery is extraordinary on multiple levels," says Dr. Laurent Davin, leading author of the paper. "Not only is this the world's earliest figurine depicting human-animal interaction, but it's also the earliest naturalistic representation of a woman found in Southwest Asia."

“The NEG II figurine captures a transformative moment,” says Prof. Grosman. “It bridges the world of mobile hunter gatherers and that of the first settled communities, showing how imagination and symbolic thinking began to shape human culture.”

Beyond its craftsmanship, the piece embodies the earliest seeds of myth, storytelling, and spiritual connection, articulated in clay by hands that lived millennia before the rise of civilization.

The remains of an extensive Bronze Age settlement on the Kazakh Steppe

 


Unearthing the City of Seven Ravines

The remains of an extensive Bronze Age settlement on the Kazakh Steppe that was likely once a major regional hub for large-scale bronze production more than 3,500 years ago, have been revealed by an international team of archaeologists co-led by researche


Aerial view of Semiyarka site 

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An aerial view of Semiyarka site taken by drone. 

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Credit: Peter J. Brown

The remains of an extensive Bronze Age settlement on the Kazakh Steppe that was likely once a major regional hub for large-scale bronze production more than 3,500 years ago, have been revealed by an international team of archaeologists co-led by researchers from UCL.

Published in Antiquity Project Gallery and co-led by Durham University and Kazakhstan’s Toraighyrov University, the paper presents the first detailed archaeological survey of Semiyarka—a vast, 140-hectare planned settlement and the largest known ancient site of its kind in the region. Although first identified in the early 2000s by researchers at Toraighyrov University, the site has only now been investigated in depth. Dating from around 1600 BC, Semiyarka offers insight into an important period of history when local nomadic communities began transitioning into permanent, urbanised settlements.

Lead author Dr Miljana Radivojević (UCL Archaeology) said: “This is one of the most remarkable archaeological discoveries in this region for decades. Semiyarka changes the way we think about steppe societies. It shows that mobile communities could build and sustain permanent, organised settlements centred on a likely large-scale industry — a true ’urban hub’ of the steppe.”

Today, what remains of the city are two rows of rectangular earthen mounds about a metre high that were the foundations of enclosed homes with multiple rooms. Nearby, the researchers also found the remains of a larger, central structure twice the size of the homes. Though its exact purpose is unclear, it could have been the site of rituals, a common communal space or may have been the home of a powerful family.

The scale and permanence of the settlement is surprising, as researchers had understood the people that lived in the region at the time to be semi-nomadic, living in mobile camps or small villages.

Co-author Professor Dan Lawrence of Durham University said: “The scale and structure of Semiyarka are unlike anything else we’ve seen in the steppe zone. The rectilinear compounds and the potentially monumental building show that Bronze Age communities here were developing sophisticated, planned settlements similar to those of their contemporaries in more traditionally ‘urban’ parts of the ancient world.”

Semiyarka was likely a major centre for tin bronze production in the region – a rare discovery in the Eurasian Steppe. On the southeast end of the city, researchers unearthed evidence of an ‘industrial zone’ dedicated to tin bronze metallurgical production, the main bronze alloy that defined the Bronze Age. Excavations and geophysical surveys revealed crucibles, slag, and tin bronze artefacts, providing the first firm evidence that Semiyarka metallurgists operated complex production systems rather than small-scale workshops.

Currently, little is known little about tin bronze production in the Eurasian Steppe Bronze Age, despite hundreds of thousands of tin bronze artefacts preserved in museum collections. Only one other settlement in eastern Kazakhstan, a Late Bronze Age mining site of Askaraly, has been linked to tin bronze production. Semiyarka shows an entire settlement zone dedicated to tin bronze making —suggesting a highly organised, possibly limited or controlled, industry of this sought-after alloy. The researchers hope that the site can offer more insights into the region’s poorly understood ancient production practices.

The city is located on a promontory above the Irtysh River in northeastern Kazakhstan and was first discovered in the early 2000s. Its name means “Seven Ravines,” taken from the network of valleys it overlooks. Its strategic location suggests that Semiyarka was once both a centre of exchange and a regional power. It’s also situated in the vicinity of copper and tin deposits in the nearby Altai Mountains which supplied the raw materials for its bronze manufacturing.

Co-author Dr Viktor Merz of Toraighyrov University in Kazakhstan, who first discovered the site, said: “I have been surveying Semiyarka for many years with the support of Kazakh national research funding, but this collaboration has truly elevated our understanding of the site. Working with colleagues from UCL and Durham has brought new methods and perspectives, and I look forward to what the next phase of excavation will reveal now that we can draw on their specialist expertise in archaeometallurgy and landscape archaeology.”

Excavated finished metallic artifacts and pottery shards indicate that the Alekseevka-Sargary people predominantly inhabited the site, a group that were some of the first to construct permanent dwellings in settlements in the region. Other items are reminiscent of the Cherkaskul people, another group that lived throughout the region but were thought to be more nomadic, indicating the inhabitants of Semiyarka likely traded with these and other local peoples.

The researchers hope in the future to examine how Semiyarka’s communities organised production and trade with their neighbours, as well as the environmental impact of these activities. In addition, the team also identified several nearby burial sites and temporary settlements from the same timeframe which could provide additional insight into the region’s ancient culture. 

Images and a copy of the final paper is available at the following link: https://drive.google.com/drive/folders/1I5NCcXPxJbAW6pam5qM44ClXPu8coT1z?usp=sharing

Saturday, November 15, 2025

Hidden signatures of ancient Rome’s master craftsmen revealed

 


Roman glasswork vessel 

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Glass openwork vessel from 300-350 CE with inscription and symbol. Inscription: ΠΙΕ ΖΗCΑΙC ΚΑΛWC ΑΕΙ (Drink, may you live well always!) (photo courtesy of Hallie G. Meredith).

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Credit: Photo courtesy of Hallie Meredith

In the hushed light of a museum gallery, Hallie Meredith discovered something intriguing about ancient Roman glasswork hiding in plain sight.

It was February 2023, and the Washington State University art history professor and glassblower was examining a private collection of Roman glass cage cups at the Metropolitan Museum of Art in New York City. These delicate works of luxury were carved from a single block of glass between 300 and 500 CE and have been studied for centuries for their beauty. Meredith’s revelation was not the result of advanced imaging or new technology but rather a simple act of curiosity: turning one of the vessels around.

On the reverse side of the late-Roman object, she found abstract openwork symbols — such as, diamonds, leaves, or crosses — carved alongside an inscription wishing its owner a long life. Previously dismissed as decorative, Meredith’s research suggests these motifs are instead makers’ marks: the signatures of workshops and artisans who carved the empire’s most intricate glass.

“Because I am trained as a maker, I kept wanting to flip things over,” said Meredith, who began glassblowing as an undergraduate in college and has continued to practice ever since. “When that happens, patterns appear that everyone else has literally photographed out of the frame.”

That moment in the museum soon grew into a larger investigation of how Roman artisans worked. In two recent papers — one published in April in the Journal of Glass Studies and another in October in World Archaeology — Meredith traced the same symbols across other carved vessels, linking them to a visual language shared by glassworkers from the fourth to sixth centuries CE. By studying tool marks, inscriptions, and unfinished fragments, she showed that these objects were not made by solitary masters but by coordinated teams of engravers, polishers, and apprentices. What began with a simple turn of the wrist revealed a hidden network of makers whose signatures, overlooked for centuries, are now coming into view.

For more than 250 years, scholars have debated how Roman glass openwork vessels were made — whether they were carved by hand, cast, or blown. Few looked beyond the inscriptions. Meredith’s findings suggest that understanding these vessels requires more than identifying their techniques; it means recognizing the people behind them.

Each cup, known as a diatretum, began as a thick-walled blank, painstakingly carved into two concentric layers linked by delicate glass bridges. The result — a lattice that seems impossibly light — was a feat of both design and endurance. Meredith’s research suggests that the work required multiple specialists collaborating over weeks, months, or even years. The abstract marks, she believes, identified collective workshops, much like a modern studio logo. “They weren’t personal autographs,” she said. “They were the ancient equivalent of a brand.”

She explores this broader world of Roman artisans in her forthcoming monograph, The Roman Craftworkers of Late Antiquity: A Social History of Glass Production and Related Industries, currently in production with Cambridge University Press and expected for release in 2026 or 2027.

Meredith’s background as a glassblower gives her research a practical edge. She knows the feel of molten glass and the discipline it takes to shape it — experience that now guides her approach to ancient craftsmanship. At WSU, she teaches Experiencing Ancient Making, a course where students 3D print versions of ancient artworks, try their hand at making, and use an app she designed to virtually take apart artifacts. “The goal isn’t perfect replication,” she said. “It’s empathy. Ancient craftworkers can be understood differently when their production processes are experienced.”

That empathy drives her larger mission to restore visibility to the anonymous artisans who shaped the ancient world. “There’s been a static picture of people who do the work,” Meredith said. “We presume we understand them because we focus on elites. But when the evidence is assembled, far more is known about these craftworkers than previously thought.”

Her next project bridges art history and data science. Working with WSU computer science students, Meredith is building a searchable database to track non-standard writing — misspellings, mixed alphabets, and coded inscriptions — across thousands of portable objects. What earlier scholars dismissed as gibberish may, she believes, be evidence of multilingual makers adapting scripts for new audiences.

Meredith’s research ultimately challenges scholars to view ancient artifacts from a new perspective. When light glances off a diatretum’s lattice, the glass reveals more than a marvel of engineering — it reflects the hands, skill, and imagination of the people who made it.

Paleogenomics: humans and dogs spread across Eurasia together

A genomic study shows that over the last 10,000 years, diverse Eurasian cultures kept and spread genetically distinct dog populations.

Dogs have been part of human societies across Eurasia for at least 20,000 years, accompanying us through many social and cultural upheavals. A new study by an international team, published in the journal Science, and led by Laurent Frantz, paleogeneticist at the Ludwig Maximilian University of Munich (LMU) and Queen Mary University of London (QMUL) shows that the spread of new cultures across Eurasia, with different lifeways, was often associated with the spread of specific dog populations.

Scientists from LMU, QMUL, the Kunming Institute of Zoology and Lanzhou University in China, and the University of Oxford, sequenced and analyzed the genomes of 17 ancient dogs from Siberia, East Asia, and the Central Asian Steppe – including, for the first time, specimens from China. Important cultural changes occurred in these regions over the past 10,000 years, driven by the dispersal of hunter-gatherers, farmers, and pastoralists. The specimens came from archaeological sites between 9,700 and 870 years old. In addition, the researchers included publicly available genomes from 57 ancient and 160 modern dogs in their analyses.

Dogs followed metalworkers across the Eurasian Steppe over 4,000 years ago

A comparison of ancient dog and human genomes reveals a striking concordance between genetic shifts in both species across time and space, most notably during periods of population turnover. This link is especially evident during China's transformative Early Bronze Age (~4,000 years ago), which saw the introduction of metalworking. The research shows that the expansion of people from the Eurasian Steppe, who first introduced this transformative technology to Western China, also brought their dogs with them.

This pattern of human-dog co-movement extends back far beyond the Bronze Age. The research traces signals of co-disperal back at least 11,000 years, when hunter-gatherers in northern Eurasia were exchanging dogs closely related to today's Siberian Huskies.

“Traces of these major cultural shifts can be teased out of the genomes of ancient dogs,” says Dr. Lachie Scarsbrook (LMU/Oxford), one of the lead authors of the study. “Our results highlight the deeply rooted cultural importance of dogs. Instead of just adopting local populations, people have maintained a distinct sense of ownership towards their own dogs for at least the past 11,000 years.”

“This tight link between human and dog genetics shows that dogs were an integral part of society, whether you were a hunter-gatherer in the Arctic Circle 10,000 years ago or a metalworker in an early Chinese city,” says Prof. Laurent Frantz. “It’s an amazing, enduring partnership and shows the sheer flexibility of the role dogs can play in our societies, far more than with any other domestic species.”

10.1126/science.adu2836  

Thursday, November 13, 2025

New discovery suggests opium use in ancient cultures, from Xerxes to King Tut

 Examination of an ancient alabaster vase in the Yale Peabody Museum’s Babylonian Collection has revealed traces of opiates, providing the clearest evidence to date of broad opium use in ancient Egyptian society, according to a new study by the Yale Ancient Pharmacology Program (YAPP). 

The finding suggests that similar ancient Egyptian alabaster vessels — all made of calcite mined from the same quarries in Egypt — including several exquisite examples discovered in the tomb of Pharaoh Tutankhamun — could also contain traces of ancient opiates, said Andrew J. Koh, YAPP’s principal investigator and the study’s lead author. 

“Our findings combined with prior research indicate that opium use was more than accidental or sporadic in ancient Egyptian cultures and surrounding lands and was, to some degree, a fixture of daily life,” said Koh, a research scientist at the Yale Peabody Museum. “We think it’s possible, if not probable, that alabaster jars found in King Tut’s tomb contained opium as part of an ancient tradition of opiate use that we are only now beginning to understand.”

The study, published in the Journal of Eastern Mediterranean Archaeology, is coauthored by Agnete W. Lassen, associate curator of the Yale Babylonian Collection, and Alison M. Crandall, YAPP’s lab manager. 

The alabaster vase is inscribed in four ancient languages — Akkadian, Elamite, Persian, and Egyptian — to Xerxes I, who ruled the Achaemenid Empire from 486 to 465 BCE. Based in Persia, the empire at its height included Egypt as well as Mesopotamia, the Levant, Anatolia, and parts of Eastern Arabia and Central Asia.  

A second inscription on the vase written in Demotic script — a simplified form of ancient Egyptian writing — indicates that it has a capacity of about 1,200 millimeters. (It is 22 centimeters tall.) Intact examples of inscribed ancient Egyptian alabaster vessels are exceptionally rare, likely numbering less than 10 in collections worldwide, the researchers noted. 

The provenances of the intact vessels are generally unknown, the researchers said, but they at least span the reigns of Achaemenid emperors Darius, Xerxes, and Artaxerxes, a period covering 550 to 425 BCE. Yale’s vase has been part of the Babylonian Collection since shortly after the assemblage of about 40,000 ancient artifacts was established at the university in 1911. 

Based at the Peabody Museum, YAPP harnesses ethnography, science, and technology to better understand how people lived thousands of years ago. Its researchers study the organic residues found on or within ancient vessels, providing insight into ancient people’s diets and lifestyles. The program has developed specific methods for analyzing organic residues — which degrade and decompose over time and are susceptible to contamination — found in artifacts in museum collections or those that have been recently excavated. 

“Scholars tend to study and admire ancient vessels for their aesthetic qualities, but our program focuses on how they were used and the organic substances they contained, knowledge that reveals a great deal of information about the daily lives of ancient peoples, included what they ate, the medicines they used, and how they spent their leisure time,” Koh said.  

For the new study, Koh’s interest was initially piqued after observing dark-brown aromatic residues inside the vase. 

YAPP’s analysis of the residues revealed definitive evidence for noscapine, hydrocotarnine, morphine, thebaine, and papaverine — well-known diagnostic biomarkers for opium. 

Researchers say the results echo the discovery of opiate residues in a group of Egyptian alabaster vessels and Cypriot base-ring juglets found in an ordinary tomb, likely a merchant family, in Sedment, Egypt, located south of Cairo, that dates to the New Kingdom, the Egyptian empire that stretched from the 16th to the 11th century BCE.

The two findings, which stretch over a millennium and across socio-economic groups, raise the distinct possibility that opium is present among the large quantity of alabaster vessels found in Tutankhamun’s tomb in the Valley of the Kings, Koh said. 

There are clear signals of opium usage that goes beyond medicinal usage and into the spiritual realm throughout antiquity, stretching from ancient Mesopotamia to Egypt and through the Aegean, he said. During Tutankhamun's lifetime, for example, people in Crete were associated with the so-called “poppy goddess” in clearly ritualistic contexts. The poppy plant is mentioned in multiple ancient texts including the Ebers Papyrus, Hippocrates, Dioscorides’s De Materia Medica, and Galen. 

Egyptologist and archaeologist Howard Carter’s discovery of Tutankhamun’s tomb in November 1922 yielded an enormous haul of artifacts, including a vast number of exquisitely preserved Egyptian alabaster vessels that likely represented the finest available during Tutankhamen’s reign, which last from 1,333 to 1,323 BCE. 

In 1933, the analytical chemist Alfred Lucas, a member of Carter’s research team, performed a cursory chemical study of the vessels, many of which contained sticky, dark brown, aromatic organics. At the time, Lucas was unable to chemically identify the organic materials, but he determined that most were not unguents or perfumes. 

“That Lucas questioned whether any of the vessels contained perfumes or unguents at all and did not identify the remaining vessel contents as primarily aromatic in nature is significant given that the prevailing conventions at the time would have pressured him to do so,” Koh said.

No further analysis of the organic materials has been conducted since Lucas’ early attempt. The vessels — along with most other artifacts from Tutankhamun’s tomb — are housed at the Grand Egyptian Museum in Giza, Egypt.

After his historic discovery, Carter had noted an ancient looting incident that targeted the contents of the alabaster vessels, the researchers said. Finger marks found inside the vessels suggested that the looters had attempted to meticulously scrape out their contents to the dregs. Many of the looted vessels contained that same dark-brown, aromatic substances that Lucas concluded were not perfumes, the researchers note. A few of the vessels were not looted and remain filled with their original contents. 

Those contents, whatever they were, were considered important enough to accompany Tutankhamen into the afterlife and to inspire grave robbers to risk their lives in an attempted theft, Koh said. 

It is unlikely, he added, that ancient people would have assigned such value to the standard unguents and perfumes of the day. 

“We now have found opiate chemical signatures that Egyptian alabaster vessels attached to elite societies in Mesopotamia and embedded in more ordinary cultural circumstances within ancient Egypt,” Koh said. “It’s possible these vessels were easily recognizable cultural markers for opium use in ancient times, just as hookahs today are attached to shisha tobacco consumption. Analyzing the contents of the jars from King Tut’s tomb would further clarify the role of opium in these ancient societies.”

Tuesday, November 11, 2025

Neanderthal DNA helps explain how faces form

 Every human face is unique, allowing us to distinguish between individuals. We know little about how facial features are encoded in our DNA, but we may be able to learn more about how our faces develop by looking at our ancient relatives, the Neanderthals. Neanderthal faces were quite distinctive from our own, with large noses, pronounced brows and a robust lower jaw. Now, scientists from the MRC Human Genetics Unit in the Institute of Genetics and Cancer at the University of Edinburgh, UK, are using the DNA of our extinct distant relatives to learn more about how faces develop and evolve. Published today in the journal Development, they show how a region of Neanderthal DNA is better at activating a jaw-forming gene than the human counterpart, revealing one potential reason for Neanderthal’s larger lower jaws.

Hannah Long (University of Edinburgh, UK), who led the study, explains that scientists have sequenced the Neanderthal genome using DNA extracted from ancient bone and says, “The Neanderthal genome is 99.7% identical to the genome of modern-day humans and the differences between species are likely responsible for altering appearance”. Both human and Neanderthal genomes consist of about 3 billion letters that code for proteins and regulate how genes are used in the cell, which makes finding regions that impact appearance like looking for a needle in a haystack. Fortunately, Long and her colleagues had an informed idea where to look first: a region of the genome that is linked to Pierre Robin sequence, a syndrome in which the lower jaw is disproportionately small. “Some individuals with Pierre Robin sequence have large deletions or DNA rearrangements in this part of the genome that change face development and limit jaw formation. We predicted that smaller differences in the DNA might have more subtle effects on face shape,” said Long.

By comparing human and Neanderthal genomes, the team found that in this region, roughly 3000 letters in length, there were just three single-letter differences between the species. Although this region of DNA doesn’t contain any genes, it regulates how and when a gene is activated, specifically a gene called SOX9, a key coordinator of the process of face development. To demonstrate that these Neanderthal-specific differences are important for the development of the face, Long and colleagues needed to show that the Neanderthal region could activate genes in the right cells at the right time as the embryo develops. The researchers simultaneously inserted the Neanderthal and human versions of the region into the DNA of zebrafish and programmed the zebrafish cells to produce different colours of fluorescent protein depending on whether the human or Neanderthal region was active. Watching the zebrafish embryos develop, the researchers found that both the human and Neanderthal regions were active in the zebrafish cells that are involved in forming the lower jaw and the Neanderthal region was more active than the human version.

“It was very exciting when we first observed activity in the developing zebrafish face in a specific cell population close to the developing jaw, and even more so when we observed that the Neanderthal-specific differences could change its activity in development,” said Long. “This led us to think about what the consequences of these differences could be, and how to explore these experimentally.” Knowing that the Neanderthal sequence was more powerful at activating genes, Long and colleagues then asked if the resulting increased activity of its target, SOX9, might change the shape and function of the adult jaw. To test this theory, they provided the zebrafish embryos with extra SOX9 and found that cells that contribute to forming the jaw occupied a larger area.

“In our lab, we are interested in exploring the impact of additional DNA sequence differences, using a technique that mimics aspects of facial development in a dish. We hope this will inform our understanding of sequence changes in people with facial conditions and inform diagnosis,” says Long. This research shows that by studying extinct species we can learn how our own DNA contributes to face variation, development and evolution.

Source: Development 

Study:  https://journals.biologists.com/dev/article-lookup/DOI/10.1242/dev.204779