̽��ֱ�� of Cambridge - ̽��ֱ�� of Tübingen

Canterbury suburbs were home to some of Britain’s earliest humans

ta385 — Wed, 22 Jun 2022 06:00:00 +0000

Archaeological discoveries made on the outskirts of Canterbury, England, confirm the presence of early humans in southern Britain between 560,000 and 620,000 years ago, making it one of the earliest known Palaeolithic sites in northern Europe.

Climate changed the size of our bodies and, to some extent, our brains

jg533 — Thu, 08 Jul 2021 09:21:51 +0000

An interdisciplinary team of researchers, led by the Universities of Cambridge and Tübingen, has gathered measurements of body and brain size for over 300 fossils from the genus Homo found across the globe. By combining this data with a reconstruction of the world’s regional climates over the last million years, they have pinpointed the specific climate experienced by each fossil when it was a living human.

̽��ֱ��study reveals that the average body size of humans has fluctuated significantly over the last million years, with larger bodies evolving in colder regions. Larger size is thought to act as a buffer against colder temperatures: less heat is lost from a body when its mass is large relative to its surface area. ̽��ֱ��results are published today in the journal Nature Communications.

Our species, Homo sapiens, emerged around 300,000 years ago in Africa. ̽��ֱ��genus Homo has existed for much longer, and includes the Neanderthals and other extinct, related species such as Homo habilis and Homo erectus.

A defining trait of the evolution of our genus is a trend of increasing body and brain size; compared to earlier species such as Homo habilis, we are 50% heavier and our brains are three times larger. But the drivers behind such changes remain highly debated.

“Our study indicates that climate - particularly temperature - has been the main driver of changes in body size for the past million years,” said Professor Andrea Manica, a researcher in the ̽��ֱ�� of Cambridge’s Department of Zoology who led the study.

He added: “We can see from people living today that those in warmer climates tend to be smaller, and those living in colder climates tend to be bigger. We now know that the same climatic influences have been at work for the last million years.”

̽��ֱ��researchers also looked at the effect of environmental factors on brain size in the genus Homo, but correlations were generally weak. Brain size tended to be larger when Homo was living in habitats with less vegetation, like open steppes and grasslands, but also in ecologically more stable areas. In combination with archaeological data, the results suggest that people living in these habitats hunted large animals as food - a complex task that might have driven the evolution of larger brains.

“We found that different factors determine brain size and body size – they’re not under the same evolutionary pressures. ̽��ֱ��environment has a much greater influence on our body size than our brain size,” said Dr Manuel Will at the ̽��ֱ�� of Tubingen, Germany, first author of the study.

He added: “There is an indirect environmental influence on brain size in more stable and open areas: the amount of nutrients gained from the environment had to be sufficient to allow for the maintenance and growth of our large and particularly energy-demanding brains.”

This research also suggests that non-environmental factors were more important for driving larger brains than climate, prime candidates being the added cognitive challenges of increasingly complex social lives, more diverse diets, and more sophisticated technology.

̽��ֱ��researchers say there is good evidence that human body and brain size continue to evolve. ̽��ֱ��human physique is still adapting to different temperatures, with on average larger-bodied people living in colder climates today. Brain size in our species appears to have been shrinking since the beginning of the Holocene (around 11,650 years ago). ̽��ֱ��increasing dependence on technology, such as an outsourcing of complex tasks to computers, may cause brains to shrink even more over the next few thousand years.

“It’s fun to speculate about what will happen to body and brain sizes in the future, but we should be careful not to extrapolate too much based on the last million years because so many factors can change,” said Manica.

This research was funded by the European Research Council and the Antarctic Science Platform.

Reference

Will, M et al: ‘Different environmental variables predict body and brain size evolution in Homo.’ Nature Communications, July 2021. DOI: 10.1038/s41467-021-24290-7

̽��ֱ��average body size of humans has fluctuated significantly over the last million years and is strongly linked to temperature. Colder, harsher climates drove the evolution of larger body sizes, while warmer climates led to smaller bodies. Brain size also changed dramatically but did not evolve in tandem with body size.

Our study indicates that climate - particularly temperature - has been the main driver of changes in body size for the past million years.

Andrea Manica

Human fossils illustrating the variation in brain (skulls) and body size (thigh bones) during the Pleistocene.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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First complete genome data extracted from ancient Egyptian mummies

sc604 — Tue, 30 May 2017 14:32:42 +0000

An international team of researchers have successfully recovered and analysed ancient DNA from Egyptian mummies dating from approximately 1400 BCE to 400 BCE, including the first genome-wide data from three individuals. ̽��ֱ��study found that modern Egyptians share more ancestry with sub-Saharan Africans than ancient Egyptians did, whereas ancient Egyptians were found to be most closely related to ancient people from the Middle East and Western Asia.

This study counters prior scepticism about the possibility of recovering reliable ancient DNA from Egyptian mummies. Despite the potential issues of degradation and contamination caused by climate and mummification methods, the authors were able to use high-throughput DNA sequencing and robust authentication methods to ensure the ancient origin and reliability of the data. ̽��ֱ��study, published in the journal Nature Communications, shows that Egyptian mummies can be a reliable source of ancient DNA, and can contribute to a more accurate and refined understanding of Egypt’s history.

Egypt is a promising location for the study of ancient populations. It has a rich and well-documented history, and its geographic location and many interactions with populations from surrounding areas, in Africa, Asia and Europe, make it a dynamic region. Recent advances in the study of ancient DNA present an opportunity to test existing understandings of Egyptian history using ancient genetic data.

However, genetic studies of ancient Egyptian mummies are rare due to methodological and contamination issues. Although some of the first extractions of ancient DNA were from mummified remains, scientists have raised doubts as to whether genetic data, especially the nuclear DNA which encodes for the majority of the genome, from mummies would be reliable, and whether it could be recovered at all.

“ ̽��ֱ��potential preservation of DNA has to be regarded with scepticism,” said Johannes Krause, Director at the Max Planck Institute for the Science of Human History and senior author of the study. “ ̽��ֱ��hot Egyptian climate, the high humidity levels in many tombs and some of the chemicals used in mummification techniques, contribute to DNA degradation and are thought to make the long-term survival of DNA in Egyptian mummies unlikely.”

For this study, the team, led by the ̽��ֱ�� of Tübingen and the Max Planck Institute for the Science of Human History in Germany, and including researchers from the ̽��ֱ�� of Cambridge, looked at genetic differentiation and population continuity over a 1,300 year timespan, and compared these results to modern populations.

̽��ֱ��team sampled 151 mummified individuals from the archaeological site of Abusir el-Meleq, along the Nile River in Middle Egypt, from two anthropological collections hosted and curated at the ̽��ֱ�� of Tübingen and the Felix von Luschan Skull Collection at the Museum of Prehistory of the Staatliche Museen zu Berlin, Stiftung Preussicher Kulturbesitz.

In total, the authors recovered partial genomes from 90 individuals, and genome-wide datasets from three individuals. They were able to use the data gathered to test previous hypotheses drawn from archaeological and historical data, and from studies of modern DNA.

“In particular, we were interested in looking at changes and continuities in the genetic makeup of the ancient inhabitants of Abusir el-Meleq,” said Alexander Peltzer, one of the lead authors of the study from the ̽��ֱ�� of Tübingen.

̽��ֱ��team wanted to determine if the investigated ancient populations were affected at the genetic level by foreign conquest and domination during the time period under study, and compared these populations to modern Egyptian comparative populations.

“There is literary and archaeological evidence for foreign influence at the site, including the presence of individuals with Greek and Latin names and the use of foreign material culture,” said co-author W. Paul van Pelt from Cambridge’s Division of Archaeology. “However, neither of these provides direct evidence for the presence of foreigners or of individuals with a migration background, because many markers of Greek and Roman identity became ‘status symbols’ and were adopted by natives and foreigners alike. ̽��ֱ��combined use of artefacts, textual evidence and ancient DNA data allows a more holistic study of past identities and cultural exchange or ‘entanglement’.”

̽��ֱ��study found that the inhabitants of Absur el-Meleq were most closely related to ancient populations in the Levant, and were also closely related to Neolithic populations from the Anatolian Peninsula and Europe. “ ̽��ֱ��genetics of the Abusir el-Meleq community did not undergo any major shifts during the 1,300 year timespan we studied, suggesting that the population remained genetically relatively unaffected by foreign conquest and rule,” said Wolfgang Haak, group leader at the Max Planck Institute for the Science of Human History, and a co-author of the paper.

̽��ֱ��data shows that modern Egyptians share approximately 8% more ancestry on the nuclear level with sub-Saharan African populations than the inhabitants of Abusir el-Meleq, suggesting that an increase in sub-Saharan African gene flow into Egypt occurred within the last 2,000 years. Possible causal factors may have been improved mobility down the Nile River, increased long-distance trade between sub-Saharan Africa and Egypt, and the trans-Saharan slave trade that began approximately 1,300 years ago.

Reference:
Verena J. Schuenemann et al. ‘Ancient Egyptian mummy genomes suggest an increase of Sub-Saharan African ancestry in post-Roman periods.’ Nature Communications (2017). DOI: 10.1038/ncomms15694

Adapted from a press release from the Max Planck Institute for the Science of Human History.

Study finds that ancient Egyptians were most closely related to ancient populations from the Middle East and Western Asia.

̽��ֱ��combined use of artefacts, textual evidence and ancient DNA data allows a more holistic study of past identities and cultural exchange.

W. Paul van Pelt

Will Scullin

Usermontu Mummy

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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