Humanity’s earliest recorded kiss occurred in Mesopotamia 4,500 years ago

Written sources document that kissing was practiced by the peoples of the ancient Middle East 4,500 years ago, conclude researchers from the University of Copenhagen and University of Oxford in a new article published in the journal Science.

Peer-Reviewed Publication

UNIVERSITY OF COPENHAGEN - FACULTY OF HUMANITIES

 

IMAGE: BABYLONIAN CLAY MODEL SHOWING A NUDE COUPLE ON A COUCH ENGAGED IN SEX AND KISSING. DATE: 1800 BC. view more 

CREDIT: © THE TRUSTEES OF THE BRITISH MUSEUM

Recent research has hypothesised that the earliest evidence of human lip kissing originated in a very specific geographical location in South Asia 3,500 years ago, from where it may have spread to other regions, simultaneously accelerating the spread of the herpes simplex virus 1.

But according to Dr Troels Pank Arbøll and Dr Sophie Lund Rasmussen, who in a new article in the journal Science draw on a range of written sources from the earliest Mesopotamian societies, kissing was already a well-established practice 4,500 years ago in the Middle East. And probably much earlier, moving the earliest documentation for kissing back 1,000 years compared to what was previously acknowledged in the scientific community.

“In ancient Mesopotamia, which is the name for the early human cultures that existed between the Euphrates and Tigris rivers in present-day Iraq and Syria, people wrote in cuneiform script on clay tablets. Many thousands of these clay tablets have survived to this day, and they contain clear examples that kissing was considered a part of romantic intimacy in ancient times, just as kissing could be part of friendships and family members’ relations,” says Dr Troels Pank Arbøll, an expert on the history of medicine in Mesopotamia.

He continues:

“Therefore, kissing should not be regarded as a custom that originated exclusively in any single region and spread from there but rather appears to have been practiced in multiple ancient cultures over several millennia.”

Dr Sophie Lund Rasmussen adds:

“In fact, research into bonobos and chimpanzees, the closest living relatives to humans, has shown that both species engage in kissing, which may suggest that the practice of kissing is a fundamental behaviour in humans, explaining why it can be found across cultures.”

Kissing as potential transmitter of disease

In addition to its importance for social and sexual behaviour, the practice of kissing may have played an unintentional role in the transmission of microorganisms, potentially causing viruses to spread among humans.

However, the suggestion that the kiss may be regarded as a sudden biological trigger behind the spread of particular pathogens is more doubtful. The spread of the herpes simplex virus 1, which researchers have suggested could have been accelerated by the introduction of the kiss, is a case in point:

“There is a substantial corpus of medical texts from Mesopotamia, some of which mention a disease with symptoms reminiscent of the herpes simplex virus 1,” Dr Arbøll remarks.

He adds that the ancient medical texts were influenced by a variety of cultural and religious concepts, and it therefore must be emphasized that they cannot be read at face value.

“It is nevertheless interesting to note some similarities between the disease known as buʾshanu in ancient medical texts from Mesopotamia and the symptoms caused by herpes simplex infections. The bu’shanu disease was located primarily in or around the mouth and throat, and symptoms included vesicles in or around the mouth, which is one of the dominant signs of herpes infection.”

“If the practice of kissing was widespread and well-established in a range of ancient societies, the effects of kissing in terms of pathogen transmission must likely have been more or less constant”, says Dr Rasmussen.

Dr Arbøll and Dr Rasmussen conclude that future results emerging from research into ancient DNA, inevitably leading to discussions about complex historical developments and social interactions – such as kissing as a driver of early disease transmission - will benefit from an interdisciplinary approach.

Read the article “The ancient history of kissing” in Science.

Genetic analysis of Indigenous Taiwanese peoples sheds light on Austronesian expansion

 The Austronesian language family is one of the largest in the world, comprising over 1,200 languages spoken from Madagascar to Hawaii. Dang Liu, Albert Min-Shan Ko and Mark Stoneking collected genome-wide data from 55 individuals from seven Taiwanese Austronesian groups and two Han-Taiwanese groups to study the genetic structure of Taiwan, the point of origin for all Austronesian-speaking peoples. There are over 20 different Indigenous groups in Taiwan, divided into “highland” and “lowland” peoples. Many lowland peoples have intermarried with Han people, and their languages are endangered or extinct. For example, the lowland Makatao showed Han admixture dated within the past 100 years. A highland group known as the Atayal showed the most distinctive genetic profile, suggestive of considerable isolation from other groups in the last 3,000 years. By including published ancient genomes in their analyses, the authors inferred little divergence between the Into- and Out-of-Taiwan groups, with the latter and the present day highland groups showing additional interactions from northern East Asia. Austronesian people from outside Taiwan are most closely related to southern highland peoples in Taiwan. 

Exactly which Indigenous group is the parent of the Austronesian diaspora is still up for debate. Haplotype-based results suggest that the Amis are the source population, which accords with a recent linguistic analysis. However, a different approach, allele-based f4 comparisons, show that the Rukai share more ancestry with groups that left Taiwan than the Amis. The authors speculate that haplotype-based results for the Amis might reflect recent back-migration and contact. According to the authors, the results of the study demonstrate the importance of considering genetic structure within Taiwan when making inferences about the Into and Out of Taiwan events. 

South Africa's desert-like interior may have been more inviting to our human ancestors

Lining the Cape of South Africa and its southern coast are long chains of caves that nearly 200,000 years ago were surrounded by a lush landscape and plentiful food.

 

During a glacial phase that lasted between 195,000 to 123,000 years ago, these caves served as refuge to a group of humans that some researchers think were the only people to survive this ice age, called Marine Isotope Stage Six, or MIS6. And in this coastal region, a lot of archaeological research has taken place. Of less interest to archaeologists has been the interior of South Africa, which was thought to be an uninhabited, inhospitable place during at least two waves of ice ages, MIS3 and 2.

 

Now, a study has shown that the region might have been more fertile and temperate during these two glacial periods than previously thought, and that the region likely played host to human populations living around a series of paleolakes. The study, led by University of Michigan archaeologist Brian Stewart, provides a more comprehensive timeline of the age and stages of these lakes, and shows human fingerprints across the region. The research, funded by the National Geographic Society, is published in the journal PNAS.

 

"There's this perennial assumption that human population centers were always along the coast and that the interior, especially the southern interior of the Karoo Desert, were largely depopulated for long stretches of time," Stewart said. "The funny thing is that one just has to go into the interior and walk around and notice that there's archaeology everywhere."

 

But to flag the region as worthy of archaeological attention, the researchers needed to show that humans could have actually lived there. The research team, an international group including researchers from South Africa, the United Kingdom and France, examined a series of super flat areas of land ringed by higher ground. They showed that these regions, called "pans" in Afrikaans, are ancient lake beds, while the areas of higher elevation that encircle them are erosional landforms and sedimentary deposits left over from their ancient shorelines.

 

This suggests that these time periods were not as dry in this region as previously thought: there would have needed to have been sustained rainfall and humidity to keep these lakes full. The more temperate climate required to sustain lakes also meant the landscape was also able to sustain both vegetation and animals required to support human populations.

 

Reconstructing the paleolakes

 

The researchers used a variety of technologies to date and reconstruct these ancient lakes, shorelines and lake bottom deposits, and to recreate the landscape of the region. 

 

These include radiocarbon dating and a technique called luminescence, which measures the radioactivity of tiny crystals of quartz or feldspar that haven't seen the light of day since they were covered by sediment tens of thousands of years earlier. While buried, electrons from radioactive elements common to all sediments get trapped in these crystal matrices at a constant rate. By measuring how many electrons accumulated in the sample and comparing that to the degree of background radioactivity, the researchers can predict its age.

 

The researchers used these techniques to date columns of sedimentary lakeshore and lake bottom deposits, called lacustrine deposits, found surrounding and within a series of three pans dotted across a region some 100,000 square miles, about the size of Texas. They also aged the shells of freshwater mollusks found scattered throughout the region and embedded within the sedimentary lake deposits.

 

An aquatic gastropod, Tomichia ventricosa, found at a pan called Swartkolkvloer, was embedded in a column of lacustrine deposits. Together, the deposits and shells were radiocarbon dated to two time periods: approximately 39-55 thousand years before present, and approximately 31-34 thousand years before present.

 

At another pan called Grootvloer, the researchers found a freshwater mollusk called Unio caffer, which required "perennial freshwater" and the presence of fish to reproduce. These shells and lacustrine deposits in this pan were dated to between approximately 20-22 thousand years before present.

 

The researchers were also able to predict the area of land the lakes encompassed, as well as how deep they were, based on the height of the lacustrine deposits ringing their shorelines. For example, they determined that the paleolake at Swartkolkvloer was about 83 miles square and 59 feet deep, while the paleolake at Grootvloer was likely about 17 miles square and 62 feet deep. Another pan called Alexanderfontein, some 300 miles northeast near the town of Kimberley, held a lake about 13.5 miles square and 48 feet deep.

 

Based on these parameters, the researchers knew the lakes would have required a climate drastically different from the one that exists in South Africa's interior today. Using a hydrological model, they determined that evaporation rates within the region were between 20% and 25% lower than what they are today, while precipitation would have been more than 200% higher at Swartkolkvloer and 88% higher at Alexanderfontein.

 

"In various parts of the interior, between about 60 to about 12,000 years ago, we can see that there were enduring phases of pretty large bodies of water kicking around what used to be thought of as an arid and inhospitable environment," Stewart said. "This was a period that used to be thought of as notoriously dry and freezing cold in the winter. But we've got this evidence for these large lakes existing during this time period."

 

The researchers say current day regions that have similar climates and rates of precipitation and evaporation are likely northern Botswana, Zambia and Zimbabwe. Based on this estimation and data found from a contemporaneous site called Equus Cave, the researchers think large grazing and browsing mammals would have thrived in this region.

 

A complex, prehistoric people

 

Scattered alongside the lakes are human artifacts such as triangular points, bladelets, weathered ostrich shells and other assemblages. Much of these are from the Middle Stone Age, which ranged from about 280,000 years ago to about 25,000 years ago, and the Later Stone Age, which lasted from 25,000 years ago right up to European contact in the 15th century.

 

"There's Middle Stone Age archaeology just everywhere," Stewart said. "You can't drive anywhere and open the car door and not step on it. It's astounding how much there is."

 

Stewart says their findings could also expand the region where archaeologists think humans became more behaviorally complex. Over the past decades, researchers have found evidence that humans living in coastal South Africa started making the leap into complex thought, showing some of the earliest signs of behavioral complexity. It was thought that both climate and nutrient stability—including the rich omega fatty acids gleaned from seafood—allowed humans here to become behaviorally modern.

 

The group's work may challenge this idea by suggesting that favorable conditions for hunter-gatherers were not confined to the coastline but probably characterized many regions as climates changed, including the interior, current-day desert.

 

"Ours is a basin-wide study with much more macro scale implications. It also involves some of these areas that are just inland of this coastal and mountain belt that's dominated the archaeological narratives for so long," Stewart said. "Just inland of this area is a region that has been, for a long time, portrayed as hostile, and it just simply appears not to have been the case for big chunks of time—with the caveat that we need information on temperature depressions to understand how humans dealt with that." 

 

Stewart says next steps will be to return to the pans to study the archaeology throughout the region to understand better how humans lived in the area.

 

Study: Paleolakes and socioecological implications of glacial "greening" of the South African interior (available upon request)

 

Ancient DNA reveals population continuity in pre-Hispanic central Mexico

 

Ancient DNA from pre-Hispanic northern and central Mexico reveals population continuity during a period of drastic environmental change, according to a new study, and provides new insights into the region’s complex and rich demographic history. Before European colonization, present-day Mexico was home to various civilizations across two main cultural areas: Aridoamerica in the north, inhabited mainly by hunter-gatherers, and Mesoamerica in the central and southern regions, where large agriculture-based cultures flourished. The distinction between these two regions has generally been based on cultural characteristics, subsistence strategies, and ecological features. Archeological evidence suggests that the border between these two regions shifted southward between 900-1300 CE due to multidecadal droughts, allegedly driving populations replacement in central Mexico by Aridoamerican peoples and perhaps the abandonment of some Mesoamerican cities. The nature of these societal changes, however, is poorly understood and based solely on archaeological evidence. While studying the genetic variation of these ancient populations could help clarify uncertainties, ancient genomic data for pre-Hispanic populations in Mexico are significantly lacking. 

Viridiana Villa-Islas and colleagues address this knowledge gap and present shotgun genome-wide data from 12 individuals and 27 mitochondrial genomes from 8 pre-Hispanic archaeological sites across Mexico, including 2 located at the shifting border between Aridoamerica and Mesoamerica. Contrary to archaeological data, Villa-Islas et al. revealed population continuity spanning the period of megadroughts and a broad preservation of the genetic structure across present-day Mexico for the last 2300 years – one that can still be observed in modern Indigenous populations. In addition, the authors also identify a contribution to pre-Hispanic populations of northern and central Mexico from two ancient unsampled “ghost” populations, demonstrating that the demographic events that gave rise to Aridoamerican and Mesoamerican populations are more complex than previously thought. 

In a related Perspective, Bastien Llamas and Xavier Roca-Rada highlight the study’s ethical and sustainable approach to paleogenomics. “The study of Villa-Islas et al. is a remarkable example of this approach because it targets a Global South region and is led and conducted by (predominantly) local researchers,” they write. “This is a considerable departure from collaboration between local scholars and laboratories from the Global North, which requires the export of samples and often leads to the relocation of local students and early-career researchers to the Global North for training.”

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JOURNAL

Science

DOI

10.1126/science.add6142 

Human ancestors preferred mosaic landscapes and high ecosystem diversity

 

IMAGE: ARTIST ILLUSTRATION OF HOMININS ARRIVING IN A MULTI-BIOME MOSAIC LANDSCAPE. SUCH ENVIRONMENTS WERE GREATLY PREFERRED BY EARLY HUMANS, ACCORDING TO A NEW STUDY PUBLISHED IN THE JOURNAL SCIENCE BY A TEAM OF SCIENTISTS FROM SOUTH KOREA AND ITALY (COPYRIGHT, IBS CENTER FOR CLIMATE PHYSICS). view more 

CREDIT: INSTITUTE FOR BASIC SCIENCE

A new study published in the journal Science by an international team finds that early human species adapted to mosaic landscapes and diverse food resources, which would have increased our ancestor’s resilience to past shifts in climate.

Our genus Homo evolved over the past 3 million years – a period of increasing warm/cold climate fluctuations. How early human species have adapted to the intensification of climate extremes, ice ages, and large-scale shifts in landscapes and vegetation remains elusive. Did our ancestors adjust to local environmental changes over time, or did they seek out more stable environments with diverse food resources? Was our human evolution influenced more by temporal changes in climate, or by the spatial character of the environment?

To test these fundamental hypotheses on human evolution and adaptation quantitively, the research team used a compilation of more than three thousand well-dated human fossil specimens and archeological sites, representing six different human species, in combination with realistic climate and vegetation model simulations, covering the past 3 million years. The scientists focused their analysis on biomes – geographic regions which are characterized by similar climates, plants, and animal communities (e.g., savannah, rainforest, or tundra).

“For the archeological and anthropological sites and corresponding ages, we extracted the local biome types from our climate-driven vegetation model. This revealed which biomes were favored by the extinct hominin species H. ergaster, H. habilis, H. erectus, H. heidelbergensis, and H. neanderthalensis and by our direct ancestors - H. sapiens.”, said Elke Zeller, Ph.D. student from the IBS Center for Climate Physics at Pusan National University, South Korea, and lead author of the study.

According to their analysis, the scientists found that earlier African groups preferred to live in open environments, such as grassland and dry shrubland. Migrating into Eurasia around 1.8 million years ago, hominins, such as H. erectus and later H. heidelbergensis and H. neanderthalensis developed higher tolerances to other biomes over time, including temperate and boreal forests. “To survive as forest-dwellers, these groups developed more advanced stone tools and likely also social skills”, said Prof. Pasquale Raia, from the Università di Napoli Federico II, Italy, co-author of the study. Eventually, H. sapiens emerged around 200,000 years ago in Africa, quickly becoming the master of all trades. Mobile, flexible, and competitive, our direct ancestors, unlike any other species before, survived in harsh environments such as deserts and tundra.

When further looking into the preferred landscape characteristics, the scientists found a significant clustering of early human occupation sites in regions with increased biome diversity. “What that means is that our human ancestors had a liking for mosaic landscapes, with a great variety of plant and animal resources in close proximity”, said Prof. Axel Timmermann, co-author of the study and Director of the IBS Center for Climate Physics in South Korea. The results indicate that ecosystem diversity played a key role in human evolution.

The authors demonstrated this preference for mosaic landscapes for the first time on continental scales and propose a new Diversity Selection Hypothesis: Homo species, and H. sapiens, in particular, were uniquely equipped to exploit heterogeneous biomes. “Our analysis shows the crucial importance of landscape and plant diversity as a selective element for humans and as a potential driver for socio-cultural developments” adds Elke Zeller. Elucidating how vegetation shifts have shaped human sustenance, the new Science study provides an unprecedented view into human prehistory and survival strategies.

The climate and vegetation model simulations, which cover the Earth’s history of the past 3 million years, were conducted on one of South Korea’s fastest science supercomputers named Aleph. “Supercomputing is now emerging as a key tool in evolutionary biology and anthropology”, said Axel Timmermann.

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JOURNAL

Science

DOI

10.1126/science.abq1288 

Tooth enamel provides clues to hunter-gatherer lifestyle of Neanderthals

 

 

IMAGE: A NEANDERTHAL PREMOLAR TOOTH FROM THE ALMONDA CAVE SYSTEM, PORTUGAL, SEEN FROM DIFFERENT ANGLES. ISOTOPES OF STRONTIUM WERE USED TO TRACK THE MOVEMENT OF THIS INDIVIDUAL OVER THE 2 TO 3 YEARS THE ENAMEL TOOK TO FORM. view more 

CREDIT: JOÃO ZILHÃO

A study by an international team of researchers, led by the University of Southampton, has given an intriguing glimpse of the hunting habits and diets of Neanderthals and other humans living in western Europe.

The scientists examined chemical properties locked inside tooth enamel to piece together how pre-historic people lived off the land around the Almonda Cave system, near Torres Novas in central Portugal almost 100 thousand years ago.

Their findings, published in the journal PNAS, show Neanderthals in the region were hunting fairly large animals across wide tracts of land, whereas humans living in the same location tens of thousands of years later survived on smaller creatures in an area half the size.

Strontium isotopes in rocks gradually change over millions of years because of radioactive processes. This means they vary from place to place depending on the age of the underlying geology. As rocks weather, the isotopic ‘fingerprints’ are passed into plants via sediments, and make their way along the food chain – eventually passing into tooth enamel.

In this study, archaeologists used a technique which laser samples enamel and makes thousands of individual strontium isotope measurements along the growth of a tooth crown. Samples were taken from two Neanderthals, dating back about 95,000 years, and from a more recent human who lived about 13,000 years ago, during the Magdalenian period.

The scientists also looked at isotopes in the tooth enamel of animals found in the cave system. Alongside strontium, they measured oxygen isotopes, which vary seasonally from summer to winter. This enabled them to establish not only where the animals ranged across the landscape, but in which seasons they were available for hunting.

The team showed that the Neanderthals, who were targeting large animals, could have hunted wild goat in the summer, whereas horses, red deer and an extinct form of rhinoceros were available all year round within about 30km of the cave. The Magdalenian individual showed a different pattern of subsistence, with seasonal movement of about 20km from the Almonda caves to the banks of the Tagus River, and a diet which included rabbits, red deer, wild goat and freshwater fish.

The researchers approximated the territory of the two different human groups, revealing contrasting results. The Neanderthals obtained their food over approximately 600 km2, whereas the Magdalenian  individuals occupied a much smaller territory of about 300 km2.

Lead author, Dr Bethan Linscott who conducted the research while at the University of Southampton and who now works at the University of Oxford said: “Tooth enamel forms incrementally, and so represents a time series that records the geological origin of the food an individual ate.

“Using laser ablation, we can measure the variation of strontium isotopes over the two or three years it takes for the enamel to form. By comparing the strontium isotopes in the teeth with sediments collected at different locations in the region, we were able to map the movements of the Neanderthals and the Magdalenian individual. The geology around the Almonda caves is highly variable, making it possible to spot movement of just a few kms.”

Co-author, Professor Alistair Pike of the University of Southampton, who supervised the research said: “This study shows just how much science has changed our understanding of archaeology in the past decade. Previously, the lives and behaviours of past individuals was limited to what we could infer from marks on their bones or the artefacts they used. Now, using the chemistry of bones and teeth, we can begin to reconstruct individual life histories, even as far back as the Neanderthals.”

Co-author, Professor João Zilhão of the University of Lisbon, who led the excavation of the Almonda caves said: “The difference in the territory size between the Neanderthal and Magdalenian individuals is probably related to population density. With a relatively low population, Neanderthals were free to roam further to target large prey species, such as horses, without encountering rival groups.  By the Magdalenian period, an increase in population density reduced available territory, and human groups had moved down the food chain to occupy smaller territories, hunting mostly rabbits and catching fish on a seasonal basis.”

Nose shape gene inherited from Neanderthals

 

IMAGE: MODERN HUMAN AND ARCHAIC NEANDERTHAL SKULLS SIDE BY SIDE, SHOWING DIFFERENCE IN NASAL HEIGHT view more 

CREDIT: DR KAUSTUBH ADHIKARI, UCL

Humans inherited genetic material from Neanderthals that affects the shape of our noses, finds a new study led by UCL researchers.

The new Communications Biology study finds that a particular gene, which leads to a taller nose (from top to bottom), may have been the product of natural selection as ancient humans adapted to colder climates after leaving Africa.

Co-corresponding author Dr Kaustubh Adhikari (UCL Genetics, Evolution & Environment and The Open University) said: “In the last 15 years, since the Neanderthal genome has been sequenced, we have been able to learn that our own ancestors apparently interbred with Neanderthals, leaving us with little bits of their DNA.

“Here, we find that some DNA inherited from Neanderthals influences the shape of our faces. This could have been helpful to our ancestors, as it has been passed down for thousands of generations.”

The study used data from more than 6,000 volunteers across Latin America, of mixed European, Native American and African ancestry, who are part of the UCL-led CANDELA study, which recruited from Brazil, Colombia, Chile, Mexico and Peru. The researchers compared genetic information from the participants to photographs of their faces – specifically looking at distances between points on their faces, such as the tip of the nose or the edge of the lips – to see how different facial traits were associated with the presence of different genetic markers.

The researchers newly identified 33 genome regions associated with face shape, 26 of which they were able to replicate in comparisons with data from other ethnicities using participants in east Asia, Europe, or Africa.

In one genome region in particular, called ATF3, the researchers found that many people in their study with Native American ancestry (as well as others with east Asian ancestry from another cohort) had genetic material in this gene that was inherited from the Neanderthals, contributing to increased nasal height. They also found that this gene region has signs of natural selection, suggesting that it conferred an advantage for those carrying the genetic material.

First author Dr Qing Li (Fudan University) said: “It has long been speculated that the shape of our noses is determined by natural selection; as our noses can help us to regulate the temperature and humidity of the air we breathe in, different shaped noses may be better suited to different climates that our ancestors lived in. The gene we have identified here may have been inherited from Neanderthals to help humans adapt to colder climates as our ancestors moved out of Africa.”

Co-corresponding author Professor Andres Ruiz-Linares (Fudan University, UCL Genetics, Evolution & Environment, and Aix-Marseille University) added: “Most genetic studies of human diversity have investigated the genes of Europeans; our study’s diverse sample of Latin American participants broadens the reach of genetic study findings, helping us to better understand the genetics of all humans.”

The finding is the second discovery of DNA from archaic humans, distinct from Homo sapiens, affecting our face shape. The same team discovered in a 2021 paper that a gene influencing lip shape was inherited from the ancient Denisovans.*

The study involved researchers based in the UK, China, France, Argentina, Chile, Peru, Colombia, Mexico, Germany, and Brazil.

* UCL News, 2021: Genes for face shape identified

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JOURNAL

Communications Biology

DOI

10.1038/s42003-023-04838-7