ADHD neanderthals

A genomic analysis in samples of Neanderthals and modern humans shows a decrease in ADHD-associated genetic variants

A genomic analysis in samples of Neanderthals and modern humans shows a decrease in ADHD-associated genetic variants

According to the study, some features like hyperactivity or impulsiveness could have been favourably selected for survival in ancestral environments dominated by a nomad lifestyle

The frequency of genetic variants associated with attention-deficit/hyperactivity disorder (ADHD) has decreased progressively in the evolutionary human lineage from the Palaeolithic to nowadays, according to a study published in the journal Scientific Reports.

The new genomic analysis compares several ADHD-associated genetic variants described in current European populations to assess its evolution in samples of the human species (Homo sapiens), modern and ancient, and in samples of Neanderthals (Homo neanderthalensis). According to the conclusions, the low tendency observed in European populations could not be explained for the genetic mix with African populations or the introgression of Neanderthal genomic segments in our genome.

The new genomic study isled by Professor Bru Cormand, from the Faculty of Biology and the Institute of Biomedicine of the University of Barcelona (IBUB), the Research Institute Sant Joan de Déu (IRSJD) and the Rare Diseases Networking Biomedical Research Centre (CIBERER), and the researcher Oscar Lao, from the Centro Nacional de Análisis Genómico (CNAG), part of the Centre for Genomic Regulation (CRG). The study, whose first author is the CNAG-CRG researcher Paula Esteller -current doctoral student at the Institute of Evolutionary Biology (IBE, CSIC-UPF)- counts on the participation of research groups of the Aarhus University (Denmark) and the Upstate Medical University of New York (United States).

TDAH neandertales
The experts Paula Esteller, Bru Cormand and Òscar Lao

ADHD: an adaptive value in the evolutionary lineage of humans?

 The attention deficit/hyperactivity disorder (ADHD) is an alteration of the neurodevelopment which can have a large impact on the life of the affected people. Featured by hyperactivity, impulsiveness and attention deficit, it is very common in modern populations -with a prevalence of 5% in children and adolescents- and can last up to adulthood.

From an evolutionary perspective, one would expect that anything detrimental would disappear among the population. In order to explain this phenomenon, several natural hypotheses have been presented -specially focused on the context of transition from the Palaeolithic to the Neolithic-, such as the known Mismatch Theory.

“According to this theory, cultural and technological changes that occurred over the last thousands of years would have allowed us to modify our environment in order to adopt it to our physiological needs in the short term. However, in the long term, these changes would have promoted an imbalance regarding the environment in which our hunter-gatherer ancestors evolved”, note the authors.

Therefore, several traits like hyperactivity and impulsiveness -typical in people with ADHD- could have been selectively favoured in ancestral environments dominated by a nomad lifestyle. However, the same features would have become non-adaptive in other environments related to more recent times (mostly sedentary).

Why is it one of the most common disorders in children and adolescents?

 The new study, based on the study on 20,000 ADHD affected people and 35,000 controls, reveals the genetic variants and alleles associated with ADHD tend to be found in genes which are intolerant to mutations that cause loss of function, which shows the existence of a selective pressure on this phenotype.

According to the authors, the high prevalence of ADHD nowadays could be a result from a favourable selection that took place in the past. Although being an unfavourable phenotype in the new environmental context, the prevalence would still be high because much time has not passed for it to disappear. However, due to the absence of available genomic data for ADHD, none of the hypothesis has been empirically contrasted so far.

“Therefore, the analysis we conducted guarantee the presence of selective pressures that would have been acting for many years against the ADHD-associated variants. These results are compatible with the mismatch theory but they suggest negative selective pressures to have started before the transition between the Palaeolithic and the Neolithic, about 10,000 years ago”, say the authors.

Reference Article:

 Esteller-Cucala, P.; Maceda, I.; Børglum, A.D.; Demontis, D.; Faraone, S.V.; Cormand, B.; Lao, O. “Genomic analysis of the natural history of attention-deficit/hyperactivity disorder using Neanderthal and ancient Homo sapiens samples”. Scientific Reports, May,  2020. Doi: 10.1038/s41598-020-65322-4

 

Press release from the University of Barcelona

italian genetic

Exploring the origins of genetic divergence within the Italian population

Genetic adaptations of early Italian ancestors to environmental changes, such as those that occurred soon after the Last Glacial Maximum, may explain some of the genetic differences between northern and southern Italian populations today, according to a study published in BMC Biology. The research suggests that northern and southern Italian populations may have begun to diverge genetically as early as 19,000-12,000 years ago and constitutes the earliest known evidence of genetic divergence in Italy so far.

A team of researchers at the University of Bologna sequenced the genomes of 38 unrelated participants from different regions in Italy, each the third generation of their family native to each region. The genomes were selected as representative of known genetic differences across the Italian population and over 17 million distinct genetic variants were found between individuals. The authors compared these variations with existing genetic data from 35 populations across Europe and the Mediterranean and with variants previously observed in 559 ancient human remains, dating from the Upper Palaeolithic (approx. 40,000 years ago) to the Bronze Age (approx. 4,000 years ago).

Prof. Marco Sazzini, lead author of the study said: “When comparing sequences between modern and ancient genome samples, we found early genetic divergence between the ancestors of northern and southern Italian groups dating back to the Late Glacial, around 19,000-12,000 years ago. Migrations during the Neolithic and Bronze Age periods, thousands of years later, then further differentiated their gene pools. Divergence between these ancestral populations may have occurred as a result of temperature rises and subsequent shrinking of glaciers across Northern Italy during this time, allowing ancestors who survived the glaciation period to move north, separating from groups who remained in the south.”

Further analyses also revealed signatures ascribable to specific biological adaptations in northern and southern Italian genomes suggestive of habitation in differing climates. The genetic history of northern Italians showed changes in the genes responsible for regulating insulin, body-heat production and fat metabolism, whilst southern Italians showed adaptations in genes regulating the production of melanin and responses to pathogens.

Prof. Sazzini said: “Our findings suggest that the ancestors of northern Italians adapted to lower environmental temperatures and the related high-calorie diets by optimising their energy metabolism. This adaptation may play a role in the lower prevalence of Type 2 Diabetes recorded in Northern Italy today. Conversely, southern Italian ancestors adapted to a warmer climate with higher UV levels by increasing melanin production, which may explain the lower incidence rates of skin cancers recorded across Southern regions. The genomes of southern Italians also showed changes in the genes encoding mucins, which play a role in protection against pathogens, and genetic variants linked to a longer lifespan. Further research in this area may help us understand how the observed genetic differences can impact population health or predisposition to a number of diseases.”

The authors caution that although correlations may be drawn between evolutionary adaptations and current disease prevalence among populations, they are unable to prove causation, or rule out the possibility that more recent gene flow from populations exposed to diverse environmental conditions outside of Italy may have also contributed to the different genetic signatures seen between northern and southern Italians today.

 

italian genetic
Adaptive events evolved by ancestors of N_ITA/S_ITA clusters and their health implications for present-day Italians. The putative selective pressures having plausibly prompted local adaptations are displayed on the left, while biological processes subjected to natural selection are reported on the map along with their impact on present-day disease susceptibility. Distribution of biological adaptations having the potential to modulate the longevity phenotype (e.g., involving the mTOR signaling, arachidonic acid metabolism, and FoxO signaling pathways) in the overall Italian population, but especially in people from Southern Italy, is represented by the arrow on the right. Putative selective pressures, biological processes, and distribution of adaptations potentially modulating longevity are color-coded as follows: N_ITA, blue; S_ITA, red. Picture from the paper, credits Sazzini, M., Abondio, P., Sarno, S. et al., CC BY 4.0

Sazzini, M., Abondio, P., Sarno, S. et al. Genomic history of the Italian population recapitulates key evolutionary dynamics of both Continental and Southern Europeans. BMC Biol 18, 51 (2020). https://doi.org/10.1186/s12915-020-00778-4

 

Press release from Springer.


millets Mongolia

How millets sustained Mongolia's empires

How millets sustained Mongolia's empires

Stable isotope analyses reveals dramatic diet diversification at the onset of the steppe's earliest empires

 

The historic economies of Mongolia are among the least understood of any region in the world. The region's persistent, extreme winds whisk away signs of human activity and prevent the buildup of sediment which archaeologists rely on to preserve the past. Today crop cultivation comprises only a small percent of Mongolia's food production, and many scholars have argued that Mongolia presents a unique example of dense human populations and hierarchical political systems forming without intensive farming or stockpiling grains.

The current study, led by Dr. Shevan Wilkin of the Max Planck Institute for the Science of Human History provides, for the first time, a detailed glimpse into the diets and lives of ancient Mongolians, underscoring the importance of millets during the formation of the earliest empires on the steppe.

Isotopic analysis and the imperial importance of millets

millets Mongolia
Mongolian landscape with pastoral herd of sheep and goats. Credits: Alicia Ventresca Miller

Collaborating with archaeologists from the National University of Mongolia and the Institute of Archaeology in Ulaanbaatar, Dr. Wilkin and her colleagues from the MPI SHH sampled portions of teeth and rib bones from 137 previously excavated individuals. The skeletal fragments were brought back to the ancient isotope lab in Jena, Germany, where researchers extracted bone collagen and dental enamel to examine the ratios of stable nitrogen and carbon isotopes within. With these ratios in hand, scientists were able to reconstruct the diets of people who lived, ate, and died hundreds to thousands of years ago.

Researchers tracked the trends in diet through the millennia, creating a "dietscape" which clearly showed significant differences between the diets of Bronze Age peoples and those who lived during the Xiongnu and Mongol Empires. A typical Bronze Age Mongolian diet was based on milk and meat, and was likely supplemented with small amounts of naturally available plants. Later, during the Xiongnu Empire, human populations displayed a larger range of carbon values, showing that some people remained on the diet common in the Bronze Age, but that many others consumed a high amount of millet-based foods. Interestingly, those living near the imperial heartlands appear to have been consuming more millet-based foods than those further afield, which suggests imperial support for agricultural efforts in the more central political regions. The study also shows an increase in grain consumption and increasing dietary diversity through time, leading up to the well-known Mongolian Empire of the Khans.

Rethinking Mongolian prehistory

Horses are still used by many for transport across Mongolia. Credits: Shevan Wilkin

The new discoveries presented in this paper show that the development of the earliest empires in Mongolia, like in other parts of the world, was tied to a diverse economy that included the local or regional production of grain. Dr. Bryan K. Miller, a co-author who studies the historical and archaeological records of Inner Asian empires, remarks that "these regimes were like most empires, in that they directed intricate political networks and sought to amass a stable surplus - in this case a primarily pastoral one that was augmented by other resources like millet."

"In this regard," Dr. Miller adds, "this study brings us one step closer to understanding the cultural processes that led humanity into the modern world."

The view that everyone in Mongolian history was a nomadic herder has skewed discussions concerning social development in this part of the world. Dr. Wilkin notes that "setting aside our preconceived ideas of what prehistory looked like and examining the archaeological record with modern scientific approaches is forcing us to rewrite entire sections of humanity's past." Dr. Spengler, the director of the archaeobotany labs at the MPI SHH, emphasizes the importance of this discovery, noting that "this study pulls the veil of myth and lore off of the real people who lived in Mongolia millennia ago and lets us peak into their lives."

millets Mongolia
Cultivated land in northern Mongolia. Credits: Alicia Ventresca Miller

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Publication information:

Title: Economic Diversification Supported the Growth of Mongolia's Nomadic Empires

Authors: Shevan Wilkin, Alicia Ventresca Miller, Bryan K. Miller, Robert N. Spengler, William T. T. Taylor, Ricardo Fernandes, Madeleine Bleasdale, Jana Zech, S. Ulziibayar, Erdene Myagmar, Nicole Boivin, Patrick Roberts

Publication: Scientific Reports

DOI: 10.1038/s41598-020-60194-0

 

Press release from the Max Planck Institute for the Science of Human History / DE


The ancient history of Neandertals in Europe

The ancient history of Neandertals in Europe

Early ancestors of the last Neandertals lived in Europe already 120,000 years ago

This is the femur of a male Neandertal from Hohlenstein-Stadel Cave, Germany. Credit: © Oleg Kuchar, Museum Ulm

Researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have retrieved nuclear genome sequences from the femur of a male Neandertal discovered in 1937 in Hohlenstein-Stadel Cave, Germany, and from the maxillary bone of a Neandertal girl found in 1993 in Scladina Cave, Belgium. Both Neandertals lived around 120,000 years ago, and therefore predate most of the Neandertals whose genomes have been sequenced to date.

Neandertals Europe
This is the Maxillary bone of a Neandertal girl from Scladina Cave, Belgium. Credit: © J. Eloy, AWEM, Archéologie andennaise

By examining the nuclear genomes of these two individuals, the researchers could show that these early Neandertals in Western Europe were more closely related to the last Neandertals who lived in the same region as much as 80,000 years later, than they were to contemporaneous Neandertals living in Siberia. "The result is truly extraordinary and a stark contrast to the turbulent history of replacements, large-scale admixtures and extinctions that is seen in modern human history", says Kay Prüfer who supervised the study.

Intriguingly, unlike the nuclear genome, the mitochondrial genome of the Neandertal from Hohlenstein-Stadel Cave in Germany is quite different from that of later Neandertals - a previous report showed that more than 70 mutations distinguish it from the mitochondrial genomes of other Neandertals. The researchers suggest that early European Neandertals may have inherited DNA from a yet undescribed population. "This unknown population could represent an isolated Neandertal population yet to be discovered, or may be from a potentially larger population in Africa related to modern humans", explains Stéphane Peyrégne who led the analysis.

 

Press release from the Max Planck Institute for Evolutionary Anthropology / Max-Planck-Institut für evolutionäre Anthropologie


Levänluhta

Breakthrough in the discovery of DNA in ancient bones buried in water

Breakthrough in the discovery of DNA in ancient bones buried in water

During the Iron Age around 300 AD something extraordinary was initiated in Levänluhta area in Isokyrö, SW Finland. The deceased were buried in a lake, and this habit was continued for at least 400 years. When trenches were dug in the local fields in mid-1800's skulls and other human bones were surfacing. These bones had been preserved almost intact in the anoxic, ferrous water. Archaeologists, historians and locals have been wondering about these finds for over 150 years now.

In 2010, a multidisciplinary research group at the University of Helsinki decided to re-investigate the mystery of Levänluhta. The site, thought to be e.g. a sacrificial spring, is exceptional even in global scale and has yielded altogether c. 75 kg human bone material. The research group, led by docent Anna Wessman, had an ambitious aim: to find who the deceased buried in Levänluhta were, and why they were exceptionally buried under water so far from dwelling sites. Now, after several years of scientific work, the group reports their results in the most recent issue of Nature. The results are part of a more extensive international study shedding light on the colonization and population history of Siberia with DNA data from ancient - up to 31 000 years old - human bones.

"In our part, we wanted especially to find out the origins of the Iron Age remains found from Levänluhta," says the group leader Anna Wessman.

New results with DNA sequencing technology

This was investigated using cutting edge ancient DNA sequencing technology, which Department of Forensic Medicine is interested in due to the forensic casework performed at the department. Professor Antti Sajantila explains that the early phases of this project were demanding.

"Unability to repeat even our own results was utterly frustrating," Sajantila tells about the first experiments in the laboratory.

The methods were developing rapidly during the international co-operation, and ultimately the first Finnish results were shown to be accurate. Yet, it was surprising that the genomes of three Levänluhta individuals clearly resembled those of the modern Sámi people.

"We understood this quite early, but it took long to confirm these findings," tells docent Jukka Palo.

Locals or by-passers?

The results were suggesting that the Isokyrö region was inhabited by Sámi people in ancient times - according to carbon datings the bones belonged to individuals that had died 500 - 700 AD. This would be a concrete proof of Sámi in southern Finland in the past. But were the people locals, recent immigrants or haphazard by-passers? To find out, other techniques than DNA were needed. The solution lied in the enamel of teeth.

Curator Laura Arppe from the Finnish Museum of Natural History tells that strontium isotopes found in the enamel strongly suggest that the individuals grew up in the Levänluhta region.

The current genomes of the people in Finland carry both eastern Uralic and western Scandinavian components, and the genome of one the Levänluhta individuals examined had clear ties to present day Scandinavians. As a whole the replacement of the Sámi people in southern and central Finland reflects the replacement processes in Siberia, clarified in the present article. This has probably been a common feature in the Northern latitudes.

"The Levänluhta project demands further studies, not only to broaden the DNA data but also to understand the water burials as a phenomenon. The question "Why?" still lies unanswered," ponders the bone specialist, docent Kristiina Mannermaa.

###

The project was funded primarily by the Emil Aaltonen Foundation and the participating researchers represented various disciplines and departments at the University of Helsinki. As authors of the current Nature publication were: Anna Wessman, Kristiina Mannermaa and Tarja Sundell (archaeology), Antti Sajantila, Jukka Palo and Mikko Putkonen (forensic medicine), and Laura Arppe (geosciences).

Levänluhta
Levänluhta Spring in Isokyrö, SW Finland. Credit: Anna Wessman 2019

Press release from the University of Helsinki


Ancient DNA from Roman and medieval grape seeds reveal ancestry of wine making

Ancient DNA from Roman and medieval grape seeds reveal ancestry of wine making

wine France Roman era
A vineyard by Pic Saint Loup Mountain in southern France. Credit: S. Ivorra CNRS/ISEM

A grape variety still used in wine production in France today can be traced back 900 years to just one ancestral plant, scientists have discovered.

With the help of an extensive genetic database of modern grapevines, researchers were able to test and compare 28 archaeological seeds from French sites dating back to the Iron Age, Roman era, and medieval period.

Utilising similar ancient DNA methods used in tracing human ancestors, a team of researchers from the UK, Denmark, France, Spain, and Germany, drew genetic connections between seeds from different archaeological sites, as well as links to modern-day grape varieties.

It has long been suspected that some grape varieties grown today, particularly well-known types like Pinot Noir, have an exact genetic match with plants grown 2,000 years ago or more, but until now there has been no way of genetically testing an uninterrupted genetic lineage of that age.

Dr Nathan Wales, from the University of York, said: "From our sample of grape seeds we found 18 distinct genetic signatures, including one set of genetically identical seeds from two Roman sites separated by more than 600km, and dating back 2,000 years ago.

"These genetic links, which included a 'sister' relationship with varieties grown in the Alpine regions today, demonstrate winemakers' proficiencies across history in managing their vineyards with modern techniques, such as asexual reproduction through taking plant cuttings."

One archaeological grape seed excavated from a medieval site in Orléans in central France was genetically identical to Savagnin Blanc. This means the variety has grown for at least 900 years as cuttings from just one ancestral plant.

This variety (not to be confused with Sauvignon Blanc), is thought to have been popular for a number of centuries, but is not as commonly consumed as a wine today outside of its local region.

The grape can still be found growing in the Jura region of France, where it is used to produce expensive bottles of Vin Jaune, as well as in parts of Central Europe, where it often goes by the name Traminer.

Although this grape is not so well known today, 900 years of a genetically identical plant suggests that this wine was special - special enough for grape-growers to stick with it across centuries of changing political regimes and agricultural advancements.

Dr Jazmín Ramos-Madrigal, a postdoctoral researcher from the University of Copenhagen, said: "We suspect the majority of these archaeological seeds come from domesticated berries that were potentially used for winemaking based on their strong genetic links to wine grapevines.

"Berries from varieties used for wine are small, thick-skinned, full of seeds, and packed with sugar and other compounds such as acids, phenols, and aromas - great for making wine but not quite as good for eating straight from the vine. These ancient seeds did not have a strong genetic link to modern table grapes.

"Based on writings by the Roman author and naturalist, Pliny the Elder, and others, we know the Romans had advanced knowledge of winemaking and designated specific names to different grape varieties, but it has so far been impossible to link their Latin names to modern varieties.

"Now we have the opportunity to use genetics to know exactly what the Romans were growing in their vineyards."

Of the Roman seeds, the researchers could not find an identical genetic match with modern-day seeds, but they did find a very close relationships with two important grape families used to produce high quality wine.

These include the Syrah-Mondeuse Blanche family - Syrah is one of the most planted grapes in the world today - and the Mondeuse Blanche, which produces a high quality AOC (protected regional product) wine in Savoy, as well as the Pinot-Savagnin family - Pinot Noir being the "king of wine grapes".

Dr Wales said: "It is rather unconventional to trace an uninterrupted genetic lineage for hundreds of years into the past. Instead of exploring broad patterns in genetic ancestry, as in most ancient DNA projects, we had to think like forensics scientists and find a perfect match in the database.

"Large databases of genetic data from modern crops and optimized palaeogenomic methods have vastly improved our ability to analyse the history of this and other important fruits.

"For the wine industry today, these results could shed new light on the value of some grape varieties; even if we don't see them in popular use in wines today, they were once highly valued by past wine lovers and so are perhaps worth a closer look."

The researchers now hope to find more archaeological evidence that could send them further back in time and reveal more grape wine varieties.

Archaeological excavation of Roman farm at Mont Ferrier site in Tourbes, France. Grape seeds closely related to Pinot Noir and Savagnin Blanc were excavated from a well dating to the first century CE. Credit: M. Compan, Inrap

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Ancient DNA sheds light on Arctic hunter-gatherer migration to North America ~5,000 years ago

Ancient DNA sheds light on Arctic hunter-gatherer migration to North America ~5,000 years ago

An ancient population of Arctic hunter-gatherers, known as Paleo-Eskimos, made a significant genetic contribution to populations living in Arctic North America today

New research reveals the profound impact of Arctic hunter-gathers who moved from Siberia to North America about 5000 years ago on present-day Native Americans. Although this group is well-known from archaeology and ancient DNA, previous genetic studies suggested that they may have been largely replaced by the groups that gave rise to present-day Arctic peoples such as the Inuit, Yup’ik, and Aleuts. The present study proves that many present-day North Americans derive significant heritage from this ancient population.

The first humans in North America arrived from Asia some time before 14,500 years ago. The next major stream of gene flow came about 5000 years ago, and is known to archaeologists as Paleo-Eskimos. About 800 years ago, the ancestors of the present-day Inuit and Yup'ik people replaced this population across the Arctic. By about 700 years ago, the archaeological evidence for the Paleo-Eskimo culture disappeared. Their genetic legacy in living populations has been contentious, with several genetic studies arguing that they made little contribution to later North Americans.

In the current study, researchers generated genome-wide data from 48 ancient individuals and 93 modern individuals from Siberia, Alaska, the Aleutian Islands and Canada, and compared this with previously published data. The researchers used novel analysis methods to create a comprehensive model of population history that included many ancient and modern groups to determine how they might be related to each other. "Our study is unique, not only in that it greatly expands the number of ancient genomes from this region, but because it is the first study to comprehensively describe all of these populations in one single coherent model," states Stephan Schiffels of the Max Planck Institute for the Science of Human History.

Paleo-Eskimos
An ancient population of Arctic hunter-gatherers, known as Paleo-Eskimos, made a significant genetic contribution to populations living in Arctic North America today. Credit: Illustration by Kerttu Majander, Design by Michelle O'Reilly

Paleo-Eskimos left a lasting legacy that extends across North America

The researchers were able to show that a substantial proportion of the genetic heritage of all ancient and modern American Arctic and Chukotkan populations comes from Paleo-Eskimos. This includes people speaking Eskimo-Aleut languages, such as the Yup'ik, Inuit and Aleuts, and groups speaking Na-Dene languages, such as Athabaskan and Tlingit speakers, in Canada, Alaska, and the lower 48 states of the United States.

Based on the researchers' analysis, Paleo-Eskimos interbred with people with ancestry similar to more southern Native peoples shortly after their arrival to Alaska, between 5,000 and 4,000 years ago. The ancestors of Aleutian Islanders and Athabaskans derive their genetic heritage directly from the ancient mixture between these two groups. The researchers also found that the ancestors of the Inuit and Yup'ik people crossed the Bering Strait at least three times: first as Paleo-Eskimos to Alaska, second as predecessors of the Old Bering Sea archaeological culture back to Chukotka, and third to Alaska again as bearers of the Thule culture. During their stay in Chukotka that likely lasted for more than 1000 years, Yupik and Inuit ancestors also admixed with local groups related to present-day Chukchi and local peoples from Kamchatka.

Paleo-Eskimo ancestry is particularly widespread today in Na-Dene language speakers, which includes Athabaskan and Tlingit communities from Alaska and northern Canada, the West Coast of the United States, and the southwest United States.

"For the last seven years, there has been a debate about whether Paleo-Eskimos contributed genetically to people living in North America today; our study resolves this debate and furthermore supports the theory that Paleo-Eskimos spread Na-Dene languages," explains David Reich of Harvard Medical School and the Howard Hughes Medical Institute. "One of the most striking case examples from our study is the ancient DNA we generated from the ancient Athabaskan site of Tochak McGrath in interior Alaska, where we worked in consultation with the local community to obtain data from three approximately seven hundred year old individuals. We found that these individuals, who lived after the time when the Paleo-Eskimo archaeological culture disappeared across North America, are well modeled as a mixture of the same two ancestry components as those found in Athabaskans today, and derived more than 40% of their ancestry from Paleo-Eskimos.

The excavation of the Middle Dorset individual from the Buchanan site on southeastern Victoria Island, Nunavut, Central Canadian Arctic. Credit: T. Max Friesen

A case example for how genetics can be combined with archaeology to shed new light on the past

The researchers hope that the paper will provide an example of the value of genetic data, in the context of archaeological knowledge, to resolve long-standing questions.

"Determining what happened to this population was not possible from the archaeological record alone," explains Pavel Flegontov of the University of Ostrava. "By analyzing genetic data in concert with the archaeological data, we can meaningfully improve our understanding of the prehistory of peoples of this region. We faced challenging analytical problems due to the complex sequence of gene flows that have shaped ancestries of peoples on both sides of the Bering Strait. Reconstructing this sequence of events required new modelling approaches that we hope may be useful for solving similar problems in other regions of the world."

Attu Island, Aleutian Islands, Alaska. Credit: Jason Rogers

Press release from the Max Planck Institute for the Science of Human History / Max-Planck-Instituts für Menschheitsgeschichte

 


DNA from 31,000-year-old milk teeth leads to discovery of new group of ancient Siberians

DNA from 31,000-year-old milk teeth leads to discovery of new group of ancient Siberians

The two 31,000-year-old milk teeth found at the Yana Rhinoceros Horn Site in Russia which led to the discovery of a new group of ancient Siberians. Credit: Russian Academy of Sciences

Two children's milk teeth buried deep in a remote archaeological site in north eastern Siberia have revealed a previously unknown group of people lived there during the last Ice Age.

The finding was part of a wider study which also discovered 10,000 year-old human remains in another site in Siberia are genetically related to Native Americans - the first time such close genetic links have been discovered outside of the US.

The international team of scientists, led by Professor Eske Willerslev who holds positions at St John's College, University of Cambridge, and is director of The Lundbeck Foundation Centre for GeoGenetics at the University of Copenhagen, have named the new people group the 'Ancient North Siberians' and described their existence as 'a significant part of human history'.

The DNA was recovered from the only human remains discovered from the era - two tiny milk teeth - that were found in a large archaeological site found in Russia near the Yana River. The site, known as Yana Rhinoceros Horn Site (RHS), was found in 2001 and features more than 2,500 artefacts of animal bones and ivory along with stone tools and evidence of human habitation.

The discovery is published today (June 5 2019) as part of a wider study in Nature and shows the Ancient North Siberians endured extreme conditions in the region 31,000 years ago and survived by hunting woolly mammoths, woolly rhinoceroses, and bison.

Professor Willerslev said: "These people were a significant part of human history, they diversified almost at the same time as the ancestors of modern day Asians and Europeans and it's likely that at one point they occupied large regions of the northern hemisphere."

Dr Martin Sikora, of The Lundbeck Foundation Centre for GeoGenetics and first author of the study, added: "They adapted to extreme environments very quickly, and were highly mobile. These findings have changed a lot of what we thought we knew about the population history of north eastern Siberia but also what we know about the history of human migration as a whole."

Researchers estimate that the population numbers at the site would have been around 40 people with a wider population of around 500. Genetic analysis of the milk teeth revealed the two individuals sequenced showed no evidence of inbreeding which was occurring in the declining Neanderthal populations at the time.

Siberia milk teeth America
Alla Mashezerskaya maps the artefacts in the area where two 31,000-year-old milk teeth were found. Credit: Elena Pavlova

The complex population dynamics during this period and genetic comparisons to other people groups, both ancient and recent, are documented as part of the wider study which analysed 34 samples of human genomes found in ancient archaeological sites across northern Siberia and central Russia.

Professor Laurent Excoffier from the University of Bern, Switzerland, said: "Remarkably, the Ancient North Siberians people are more closely related to Europeans than Asians and seem to have migrated all the way from Western Eurasia soon after the divergence between Europeans and Asians."

Scientists found the Ancient North Siberians generated the mosaic genetic make-up of contemporary people who inhabit a vast area across northern Eurasia and the Americas - providing the 'missing link' of understanding the genetics of Native American ancestry.

It is widely accepted that humans first made their way to the Americas from Siberia into Alaska via a land bridge spanning the Bering Strait which was submerged at the end of the last Ice Age. The researchers were able to pinpoint some of these ancestors as Asian people groups who mixed with the Ancient North Siberians.

Professor David Meltzer, Southern Methodist University, Dallas, one of the paper's authors, explained: "We gained important insight into population isolation and admixture that took place during the depths of the Last Glacial Maximum - the coldest and harshest time of the Ice Age - and ultimately the ancestry of the peoples who would emerge from that time as the ancestors of the indigenous people of the Americas."

This discovery was based on the DNA analysis of a 10,000 year-old male remains found at a site near the Kolyma River in Siberia. The individual derives his ancestry from a mixture of Ancient North Siberian DNA and East Asian DNA, which is very similar to that found in Native Americans. It is the first time human remains this closely related to the Native American populations have been discovered outside of the US.

Professor Willerslev added: "The remains are genetically very close to the ancestors of Paleo-Siberian speakers and close to the ancestors of Native Americans. It is an important piece in the puzzle of understanding the ancestry of Native Americans as you can see the Kolyma signature in the Native Americans and Paleo-Siberians. This individual is the missing link of Native American ancestry."

 

Press release from the St John's College, University of Cambridge

 


East Africa

Ancient DNA tells the story of the first herders and farmers in east Africa

Ancient DNA tells the story of the first herders and farmers in east Africa

A collaborative study that includes a SLU-Madrid archaeologist provides new insights on early human interaction

East Africa
Herders move goats through the Engaruka Basin in northern Tanzania's Rift Valley. Ancient DNA shows that this way of life spread to East Africa through multiple population movements. Credit: Katherine Grillo

ST. LOUIS, MO (May 30, 2019) - A collaborative study led by archaeologists, geneticists and museum curators is providing answers to previously unsolved questions about life in sub-Saharan Africa thousands of years ago. The results were published online in the journal Science Thursday, May 30.

Researchers from North American, European and African institutions analyzed ancient DNA from 41 human skeletons curated in the National Museums of Kenya and Tanzania, and the Livingstone Museum in Zambia.

"The origins of food producers in East Africa have remained elusive because of gaps in the archaeological record," said co-first author Mary Prendergast, Ph.D., professor of anthropology and chair of humanities at Saint Louis University's campus in Madrid, Spain.

"This study uses DNA to answer previously unresolvable questions about how people were moving and interacting," added Prendergast.

The research provides a look at the origins and movements of early African food producers.

The first form of food production to spread through most of Africa was the herding of cattle, sheep and goats. This way of life continues to support millions of people living on the arid grasslands that cover much of sub-Saharan Africa.

"Today, East Africa is one of the most genetically, linguistically, and culturally diverse places in the world," explains Elizabeth Sawchuk, Ph.D., a bioarchaeologist at Stony Brook University and co-first author of the study. "Our findings trace the roots of this mosaic back several millennia. Distinct peoples have coexisted in the Rift Valley for a very long time."

Previous archaeological research shows that the Great Rift Valley of Kenya and Tanzania was a key site for the transition from foraging to herding. Herders of livestock first appeared in northern Kenya around 5000 years ago, associated with elaborate monumental cemeteries, and then spread south into the Rift Valley, where Pastoral Neolithic cultures developed.

The new genetic results reveal that this spread of herding into Kenya and Tanzania involved groups with ancestry derived from northeast Africa, who appeared in East Africa and mixed with local foragers there between about 4500-3500 years ago. Previously, the origins and timing of these population shifts were unclear, and some archaeologists hypothesized that domestic animals spread through exchange networks, rather than by movement of people.

After around 3500 years ago, herders and foragers became genetically isolated in East Africa, even though they continued to live side by side. Archaeologists have hypothesized substantial interaction among foraging and herding groups, but the new results reveal that there were strong and persistent social barriers that lasted long after the initial encounters.

Another major genetic shift occurred during the Iron Age around 1200 years ago, with movement into the region of additional peoples from both northeastern and western Africa. These groups contributed to ancient ancestry profiles similar to those of many East Africans today. This genetic shift parallels two major cultural changes: farming and iron-working.

The study provided insight into the history of East Africa as an independent center of evolution of lactase persistence, which enables people to digest milk into adulthood. This genetic adaptation is found in high proportions among Kenyan and Tanzanian herders today.

Co-first author Mary Prendergast, Ph.D., is a professor of anthropology and chair of humanities at Saint Louis University's campus in Madrid, Spain. Credit: Mary Prendergast

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Uralic languages Siberia

Ancient DNA suggests that some Northern Europeans got their languages from Siberia

Ancient DNA suggests that some Northern Europeans got their languages from Siberia

Uralic languages Siberia
Estonian Grammar by Heinrich Stahl, published 1637 in Reval (Tallinn). Public Domain

Most Europeans descend from a combination of European hunter-gatherers, Anatolian early farmers, and Steppe herders. But only European speakers of Uralic languages like Estonian and Finnish also have DNA from ancient Siberians. Now, with the help of ancient DNA samples, researchers reporting in Current Biology on May 9 suggest that these languages may have arrived from Siberia by the beginning of the Iron Age, about 2,500 years ago, rather than evolving in Northern Europe.

The findings highlight the way in which a combination of genetic, archaeological, and linguistic data can converge to tell the same story about what happened in particular areas in the distant past.

"Since the transition from Bronze to Iron Age coincides with the diversification and arrival time of Finnic languages in the Eastern Baltic proposed by linguists, it is plausible that the people who brought Siberian ancestry to the region also brought Uralic languages with them," says Lehti Saag of University of Tartu, Estonia.

Although researchers knew that the Uralic-speaking people share common Siberian ancestry, its arrival time in the Eastern Baltic had remained uncertain. To characterize the genetic ancestry of people from the as-yet-unstudied cultural layers, Saag along with Kristiina Tambets and colleagues extracted DNA from the tooth roots of 56 individuals, 33 of which yielded enough DNA to include in the analysis.

"Studying ancient DNA makes it possible to pinpoint the moment in time when the genetic components that we see in modern populations reached the area since, instead of predicting past events based on modern genomes, we are analyzing the DNA of individuals who actually lived in a particular time in the past," Saag explains.

Their data suggest that the Siberian ancestry reached the coasts of the Baltic Sea no later than the mid-first millennium BC--around the time of the diversification of west Uralic/Finnic languages. It also indicates an influx of people from regions with strong Western hunter-gatherer characteristics in the Bronze Age, including many traits we now associate with modern Northern Europeans, like pale skins, blue eyes, and lactose tolerance.

"The Bronze Age individuals from the Eastern Baltic show an increase in hunter-gatherer ancestry compared to Late Neolithic people and also in the frequency of light eyes, hair, and skin and lactose tolerance," Tambets says, noting that those characteristics continue amongst present-day Northern Europeans.

The researchers are now expanding their study to better understand the Iron Age migration processes in Europe. They say they will also "move forward in time and focus on the genetic structure of the medieval time period."

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