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人類學 – 開欄文
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從DNA了解德尼索文人-Linda Ongaro
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Their DNA Still Lives in Us, But Who Were the Denisovans?
Linda Ongaro, 11/26/24
請至原網頁觀看照片
It started with a finger bone found in a cave in the Altai mountains in Siberia in the late 2000s. Thanks to advances in DNA analysis, this was all that was required for scientists to be able to identify an entirely new group of hominins, meaning upright primates on the same evolutionary branch as humans.
Now known as the Denisovans (De-NEES-ovans), after the Denisova cave in which the finger bone was found, the past few years have seen numerous other discoveries about these people. I’ve recently co-published a paper collating everything we know so far.
So who were the Denisovans, where did they live, and why are they important to the story of humanity?
Around 600,000 years ago, early humans in Africa diverged into groups. Some migrated out of Africa, becoming Neanderthals in eastern and western Eurasia and Denisovans in eastern Eurasia.
Modern humans later evolved in Africa, spread across the globe, and encountered Neanderthals, Denisovans and possibly other unknown archaic human groups. Yet by 40,000 years ago, only modern humans remained on the archaeological record.
The genetic legacy
Unlike Neanderthals, whose fossils are relatively abundant, Denisovan remains continue to be very scarce. Apart from that Siberian finger bone, the main other discovery was a jawbone found in China, in a limestone cave located on the northeastern edge of the Tibetan Plateau. It had been believed that the Denisovans had been confined to Siberia, but this jawbone demonstrated that they had lived much further afield.
Their DNA has enabled scientists to build on this insight, since it survives in contemporary populations, particularly in Oceania, parts of Asia, and even Indigenous American populations. This shows that the Denisovans were widely distributed across these areas.
From Tibet to the Americas, the Denisovans certainly got around. Dmitry Kalinovsky 請至原網頁觀看照片
Strikingly, recent studies reveal that Denisovans interbred with modern humans multiple times. For instance, east Asians harbour ancestry from at least two distinct Denisovan populations. Also, the people of Papua New Guinea, which retain up to 5% Denisovan ancestry, a much higher proportion than other groups, interbred with at least two Denisovan groups at different times.
Additionally, research has shown that some populations from the Philippines carry a distinct Denisovan ancestry compared to their neighbouring groups. These various genetic differences highlight that the interbreeding between modern humans and Denisovans has a complex history.
Adaptations
While much about the Denisovans’ lifestyle, appearance and culture remains unknown, the discovery of the Tibetan jawbone showed that these people lived in diverse environments, and that they must have been very adaptable. Sure enough, we now know that Denisovan ancestry in modern humans has contributed to adaptive traits, particularly in challenging environments.
A notable example is the EPAS1 gene. Inherited from Denisovans, it helps regulate the body’s response to low oxygen levels, giving Tibetans a physiological advantage in the high altitudes of the Tibetan plateau.
Other human adaptations possibly derived from Denisovan interbreeding relate to being able to tolerate cold weather, and being able to metabolise lipids, which include fats and oils. These may have been beneficial for populations in northern regions, such as the Arctic. For example, Inuit populations carry Denisovan genes that help to regulate body fat and maintain warmth.
The Inuit may have the Denisovans to thank for their ability to tolerate harsh climes. Chris Christopherson 請至原網頁觀看照片
Some genes that aid in fighting infections also appear to have Denisovan origins. These immune-related genes might have played crucial roles in protecting ancient and modern humans from south and east Asia, the Americas and Papua New Guinea against specific pathogens, illustrating how Denisovan heritage continues to affect human health today.
Unanswered questions
Many questions about the Denisovans remain unanswered. For instance, how genetically distinct were these populations, and how many distinct groups existed? We know that at least four distinct Denisovan populations interbred with modern humans. However, with further analyses, this number might increase, revealing an even more complex story.
We’re also looking for a better understanding of the biological impact of Denisovan DNA in modern humans. While many beneficial traits have been identified as derived from Neanderthals, only a few have been found for Denisovans so far. Many other potential contributions remain to be explored.
This will be possible only if additional Denisovan remains are discovered and DNA is extracted and sequenced. We need more data, especially from diverse geographical regions and time periods, to provide new insights into these people’s adaptations, interactions with other hominins, and lasting legacy in human evolution.
The first reconstruction of a Denisovan, from Hebrew University in 2019. UPI/Alamy 請至原網頁觀看照片
To address these questions, our research capabilities will need to improve. For example, we need new tools to more accurately distinguish Denisovan genetic material from Neanderthal and modern human DNA.
Additionally, studying Denisovan ancestry in populations beyond east Asia and Oceania, such as Indigenous Americans, could shed light on exactly which Denisovan sources have contributed to modern humans genomes.
The discoveries to date highlight the power of genetic studies in uncovering hidden chapters of our past. Each discovery brings us closer to understanding who the Denisovans were and how their lives and adaptations continue to affect humans today.
Linda Ongaro, Research Fellow in Genetics, Trinity College Dublin
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露西給人類學帶來的啟示 ---- M. Marshall/C. Barras
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How we misunderstood what the Lucy fossil reveals about ancient humans
It has been 50 years since archaeologists discovered Lucy, perhaps the most famous ancient hominin ever found. But the scientists who have studied her say that this fossil gave us a misleading image of the nature of her species
Michael Marshall/Colin Barras, 11/15/24
A reconstruction of the famous hominin Lucy, Frank Nowikowski/Alamy 請至原網頁觀看照片(需訂閱)
This is an extract from Our Human Story, our newsletter about the revolution in archaeology. Sign up to receive it in your inbox every month.
One hundred years ago, on 28 November 1924, anthropologist Raymond Dart opened a crate. It held a consignment of fossils from Taung, a quarry in South Africa, including a small skull that looked part-ape, part-human. Dart named it “Australopithecus africanus: The Man-Ape of South Africa”. It was the first Australopithecus specimen to be identified, and the first evidence that early humans evolved in Africa – instead of Eurasia as was widely assumed at the time. The importance of the “Taung Child”, as it’s known, is crystal clear.
Half a century later, Donald Johanson and his colleagues were excavating in the Afar region of Ethiopia. They found a partial skeleton on 24 November 1974 – almost 50 years to the day after Dart opened his crate. During the subsequent celebrations, they played the Beatles song Lucy in the Sky with Diamonds, and expedition member Pamela Alderman suggested calling the skeleton “Lucy”.
Later, this ancient human also got a scientific name: Australopithecus afarensis. But the name “Lucy” stuck and became part of pop culture, in a way that “the Taung Child” hadn’t. Nowadays it is the done thing to assign names to significant hominin specimens: hence we have the famous fossils known as Neo, Selam and Denny.
(Incidentally it has also been 20 years since the publication of the papers describing another ancient human species, the “hobbits”, Homo floresiensis, from Flores in Indonesia. However, the remains were found in 2003, so I’m not counting it as a major anniversary. Likewise, the species Homo habilis was first described in 1964, 60 years ago, but the remains were found several years earlier.)
So, what made Lucy such a big deal?
Donald Johanson assembles the Lucy skeleton for the first time with French colleague Maurice Taiebe in 1974, Institute of Human Origins, Arizona State University 請至原網頁觀看照片(需訂閱)
Lucy is one of those stories that I have heard a few times too often. I was born in the early 1980s, some years after the discovery. When I became interested in human evolution, Lucy’s discovery was an established myth, endlessly told and retold.
As a result, my relationship to Lucy is a bit like my relationship to the Beatles: they belong to my parents’ generation. The band’s music is so influential, so widely copied, that it takes a hefty imagination to understand what it must have been like to experience it as brand new: to hear that dramatic suspended chord at the start of A Hard Day’s Night or the dissonant wails of Tomorrow Never Knows, and know that you’ll never listen to music quite the same way again.
On a side note: some years ago, when I was a staff writer for New Scientist and working in the London office, a group of us who were interested in human evolution discussed our favourite species. I realise now that we all picked groups that had been discovered in the 21st century: the hobbits, Australopithecus sediba and (my pick) the Denisovans. Those were the ones that “belonged” to our generation.
Anyhow, when it comes to human evolution, Lucy is now part of the furniture. But in 1974 she was a novelty.
Lucy is held up as an amazing single find. And she is: the skeleton is about 40 per cent complete, including bits of the skull, ribcage, arms and legs. Having this many bones from a single individual reveals things you couldn’t see if you had the same number of bones, but from several dozen individuals.
“You can look at body proportions,” says Carol Ward at the University of Missouri. By studying the relative lengths of Lucy’s limbs, and other details, we can see that she walked bipedally. “She was just as good as you or I walking across the savannah.” Likewise, from her teeth and other clues, we can get a sense of her diet – which was plant-heavy.
And so we started to paint a picture of a species based on this one specimen. The thing is, Lucy is not a typical A. afarensis.
The remains of Lucy on display at the National Museum of Ethiopia, Edwin Remsberg/Alamy 請至原網頁觀看照片(需訂閱)
Today we have more fossils of A. afarensis than of most other hominins. “Lucy stands out as the smallest,” says Tim White at the University of California, Berkeley. “If you played the tape again and only Lucy were found, you’d have a fundamentally misleading image of what afarensis is.” He says it would be like if aliens abducted a human at random and got diminutive 1970s gymnast Olga Korbut, then tried to estimate our average height.
“Any time we find a fossil, we can’t assume that this is going to be the absolute average individual,” says Ward.
However, the year after Lucy was found, Johanson’s team made an equally seismic discovery at a nearby site: over 200 hominin bones belonging to at least 13 individuals. They are probably all A. afarensis, like Lucy, and date from the same time: 3.2 million years ago. Technically known as “A.L. 333” (meaning, fossil number 333 from the Afar Locality), they are nicknamed the “First Family”.
“That afarensis sample is the gold standard for all early hominids until Neanderthals,” says Ward. Because so many individuals are preserved, “we actually have a window into variation in one species in the past”.
This makes it easier to decide if a new specimen represents a new species or is just another A. afarensis. “We have young and old individuals, we can say something about growth,” says Ward. “We have males and females, you can talk about dimorphism and social behaviour.”
The fact so many individuals were found together implies that A. afarensis lived in groups, says Johanson, who is now at Arizona State University. “Males and females lived together with offspring,” he says. “That, to me, was quite remarkable.” In contrast, he points out, the Taung Child from 50 years earlier was found in isolation.
Raymond Dart with the Taung child fossil, Science History Images/Alamy 請至原網頁觀看照片(需訂閱)
Lucy is best understood as part of the broader collection of A. afarensis fossils from that time period. Taken as a set, these bones paint a picture of a population of hominins roaming the Ethiopian landscape. They show us A. afarensis, not as a single data point on the line between apes and humans, but as living, breathing hominins that walked around and ate and had babies. Lucy may have personalised extinct hominins for the first time, but the First Family diversified them.
For White, the biggest discoveries in palaeo-anthropology have been the ones where lots of individuals are found together. A.L. 333 is one such example. He also cites the Aramis horizon in Ethiopia, which has yielded Ardipithecus, Australopithecus and Homo remains; Dmanisi in Georgia, with its Homo erectus remains that told us a lot about the first hominin to live outside Africa; and Sima de los Huesos in northern Spain, which holds the remains of early Neanderthals.
What unites these sites, argues White, is that they allow you to study a species in something approximating its full richness, rather than simply how it differs from another species.
Ward offers another perspective on the importance of spectacular fossils like Lucy. “Big finds are truly remarkable,” she says. “What they do is, they don’t answer the questions: they bring up the new questions.” When Johanson and his team found Lucy, by extension they also found her entire species – and that raised all sorts of questions that could only be answered by more A. afarensis fossils.
“The hard part of science is not answering questions,” says Ward. “It’s knowing which questions to ask, because if you don’t ask the right questions, you’ll never get the right answers.” The lasting importance of Lucy, and the Taung Child for that matter, is that they prompted people to ask new questions. I never want to hear the story about the song ever again, but so long as Lucy keeps triggering new ideas and questions, she’ll continue to be important.
Read more：
How the secrets of ancient cuneiform texts are being revealed by AI
Why did humans evolve big brains? A new idea bodes ill for our future
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猿類演化地區-T. Kokkinidis
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Fossils in Greece Suggest Human Ancestors Evolved in Europe, Not Africa
Tasos Kokkinidis, 11/20/24
This upper mandible was found in Nikiti in northern Greece. Credit: New Scientist/David Begun 請至原網頁觀看照片
A recent analysis of fossils recovered in the 1990s in the village of Nikiti in northern Greece supports the controversial theory that apes, the ancestors of humans, evolved in Southeastern Europe instead of Africa.
The 8 or 9-million-year-old fossils had first been linked to the extinct ape called Ouranopithecus.
However, a team led by David Begun from the University of Toronto’s Department of Anthropology has recently analyzed the remains and determined that they likely belonged to a male animal from a potentially new species.
By inspecting the upper and lower jaw of the ancient European ape, the team suggested that humanity’s forebears may have evolved in Europe before migrating to Africa, potentially upending a scientific consensus that has stood since Darwin’s day.
In 1871, Darwin proposed that all hominins, including both modern and extinct humans, descended from a group in Africa. This is the most widely accepted theory today.
Fossils in Greece belong to human ancestors
On the other hand, Darwin also speculated that hominins could also have originated in Europe, where fossils of large apes had already been discovered. The new analysis supports this theory.
While Begun does not believe the ape in Greece was a hominin, he speculates that it could represent the group from which hominins directly evolved.
The research team led by Begun had determined in 2017 that a 7.2-million-year-old ape called Graecopithecus, which also lived in what is now Greece, could be a hominin.
In this case, the 8-million to 9-million-year-old Nikiti ape would have directly preceded the first hominin, Graecopithecus, before hominins migrated to Africa seven million years ago.
According to a report in the journal New Scientist, Begun foresees that this new concept will be rejected by many experts who believe in African hominin origins, but he hopes that the new scenario will at least be considered.
Begun points out that Southeastern Europe was once occupied by the ancestors of animals such as the giraffe and rhino. “It’s widely agreed that this was the found fauna of most of what we see in Africa today,” he told New Scientist. “If the antelopes and giraffes could get into Africa 7 million years ago, why not the apes?”
Not all anthropologists agree with Begun and his team’s conclusions. As noted by New Scientist, the Nikiti ape may be completely unrelated to hominins. It may have evolved similar features independently, developing teeth to eat similar foods or chew similarly to early hominins.
Related:
Homo Sapiens May Not Have Been the First Species to Use Fire
See all the latest news from Greece and the world at Greekreporter.com. Contact our newsroom to report an update or send your story, photos and videos. Follow GR on Google News and subscribe here to our daily email!
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林德索人消失之謎可能有解 -- Katie Hunt
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Cave discovery in France may explain why Neanderthals disappeared, scientists say
Katie Hunt, CNN, 09/12/24
When archaeologist Ludovic Slimak unearthed five teeth in a rock shelter in France’s Rhône Valley in 2015, it was immediately obvious that they belonged to a Neanderthal, the first intact remains of the ancient species to be discovered in that country since 1979.
However, the once-in-a-lifetime find, nicknamed Thorin after a character in “The Hobbit,” remained a well-kept secret for almost a decade while Slimak and his colleagues untangled the significance of the find — a fraught undertaking that pitted experts in ancient DNA against archaeologists.
“We faced a major issue,” said Slimak, a researcher at France’s National Centre for Scientific Research and Paul Sabatier University in Toulouse. “The genetics was sure the Neanderthal we called Thorin was 105,000 years old. But we knew by (the specimen’s) archaeological context that it was somewhere between 40,000 to 50,000 years old.”
“What the DNA was suggesting was not in accordance with what we saw,” he added.
It took the team almost 10 years to piece together the story of the puzzling Neanderthal, adding a new chapter in the long-standing mystery of why these humans disappeared around 40,000 years ago.
The research, published Wednesday in the journal Cell Genomics, found that Thorin belonged to a lineage or group of Neanderthals that had been isolated from other groups for some 50,000 years. This genetic isolation was the reason Thorin’s DNA seemed to come from an earlier time period than it actually did.
Until now, geneticists thought that at the time of extinction there was one Neanderthal population that was genetically homogeneous, but the new study reveals at least two populations were present in Western Europe at that time — and they lived surprisingly close to each other.
“The Thorin population spent 50,000 years without exchanging genes with other Neanderthal populations,” Slimak said in a news release.
“We thus have 50 millennia during which two Neanderthal populations, living about ten days’ walk from each other, coexisted while completely ignoring each other.”
Slimak said that the discovery suggested that Neanderthal communities were small and insular — factors that could be key to understanding their extinction because isolation is generally considered to be an evolutionary disadvantage.
Less genetic variation could make it harder to adapt to changing climate or disease, while less social interaction between groups makes it harder to share knowledge and technology.
“They were happy in their valley and did not need to move, while Homo sapiens all the time they want to explore, to see what is there after this river, after this mountain. (We have) this need, this need to move, and this need to build a social network,” Slimak said.
This pattern of small populations, isolated culturally and genetically from one another, was likely a major factor behind Neanderthal extinction, which occurred around the same time Homo sapiens arrived in Europe, he said.
DNA from Homo sapiens fossils from that time show that these early arrivals interbred with Neanderthals — traces of those encounters remain in present-day human populations. However, no corresponding genetic evidence of that interbreeding has been found in Neanderthal fossils from that time, including Thorin’s remains, the study noted.
Whatever behavior led to this lack of genetic intermingling on one side, along with small and isolated Neanderthal populations such as the one Slimak and his colleagues identified, likely contributed to the disappearance of the Neanderthals, said Chris Stringer, research lead in human evolution at London’s Natural History Museum who wasn’t involved in the study.
“Whatever the reasons for this imbalance (social, biological?) it contributed to the demise of the last Neanderthals, since their already small populations were losing reproductive age individuals to the other species, without any replenishment in return,” Stringer said via email.
“Coupled with economic competition from the newcomers over resources, this could have been a recipe for demographic collapse.”
It’s not clear whether Thorin’s full skeleton is interred within Grotte Mandrin, as the rock shelter in the Rhône Valley near Malataverne, France, is known. The remains were found near the surface in soft, unstable ground, and the excavation continues slowly, Slimak said, with archaeologists tweezing out “one grain at a time.” It’s also unclear whether the specimen, which is male, was deliberately buried or not.
Archaeologists have excavated more of Thorin’s remains: 31 teeth, part of the jaw and five finger bones, so far. The shape of his teeth is typical of a Neanderthal, but he had two extra lower molars — a trait sometimes suggestive of an inbred population, the study noted.
Genetic mystery resolved
The initial genetic analysis suggested that Thorin was much older because his genome was distinct from other later Neanderthals, resembling the genomes of ancient humans who lived more than 100,000 years ago.
To understand Thorin’s origins and confirm the age of his remains, the team analyzed chemical isotopes in his bones and teeth to infer what type of climate he lived in based on the water he would have drunk and other factors. A Neanderthal in Europe 105,000 years ago would have a enjoyed a much warmer climate than one living 45,000 years ago during the Ice Age.
“We worked for seven years to find out who was wrong — archaeologists or genomicists,” Slimak said in the news release.
Slimak has been involved in the excavation of Grotte Mandrin for more than three decades and made a number of exciting finds at the rock shelter. It’s the only known site to have been home to alternating groups of both Homo sapiens and Neanderthals, plus the earliest evidence of bow and arrow use outside Africa.
“Grotte Mandrin keeps delivering surprises,” Stringer said.
For more CNN news and newsletters create an account at CNN.com
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史前人的智慧 -- Darren Orf
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此之謂：「窮則變；變則通」；或：「需要為發明之母」。
Archaeologists Figured Out How Early Humans Killed Ice Age Mammoths. It’s Not How You Think.
190(ish) pounds versus six tons isn’t exactly a fair fight—but our earliest ancestors evened the playing field.
Darren Orf, 08/29/24
* Depictions of ancient humans in both scientific and popular culture contexts picture them throwing spears at the thick hides of mammoths.
* A new study from archaeologists at UC Berkeley suggests that Pleistocene hunters likely used planted pikes, topped with sharp Clovis points, to kill megafauna like mammoths, mastodons, and even saber-toothed cats.
* This theory shows how this system would’ve acted like an ancient hollow-point bullet and delivered a more devastating blow compared to a thrown spear.
It’s been long suggests that the arrival of Homo sapiens in the Americas caused (or at very least contributed to) the disappearance of megafauna like mammoths through overhunting—but how exactly did a collection of small, fragile humans take down these four-to-six ton behemoths some 13,000 years ago?
The typical depiction of humans hunting mammoths toward the tail of the Pleistocene imagines them chucking spears, tipped with sharp rocks known as Clovis points, as the beasts rear up on their hind legs in fury, but a new study from archaeologists at UC Berkeley think that ancient humans likely worked smarter, not harder.
Instead of throwing spears, which likely would’ve had little impact force on the animal, this new study published in the journal PLOS One says that hunters likely planted their spears in the ground and waited for charging mastodons, bison, or even saber-toothed cats to impale themselves upon the fearsome spiked tips. This would have driven the spear much deeper into the animals, almost acting like a modern hollow-point bullet, according to the researchers.
“This ancient Native American design was an amazing innovation in hunting strategies,” UC Berkeley’s Scott Byram, first author of the study, said in a press statement. “This distinctive Indigenous technology is providing a window into hunting and survival techniques used for millennia throughout much of the world.”
This mystery initially began with the discovery of Clovis points, an array of various-sized sharp rocks made from material like flint or jasper that use fluted indentations at the base of the stone. This rock is one of the most common archaeological items found during this period, but experts weren’t exactly sure how they used them, as the Clovis point is usually the only part of the weapon system that survives the ravages of time.
After analyzing historical records of people hunting or fighting with planted pikes, the team also designed a test platform to see how much force a spear could withstand before snapping. Similar experiments that launched spiked weapons at ballistic gels showed that a spear, thrown at an animal like a mastodon, would’ve felt like little more than a pinprick, the researchers say. But the foreshaft collapse following the Clovis point's entry into an animal’s hide likely would’ve increased the damage.
“The kind of energy that you can generate with the human arm is nothing like the kind of energy generated by a charging animal,” UC Berkeley’s Jun Sunseri, a co-author of the study, said in a press statement. “It’s an order of magnitude different. These spears were engineered to do what they’re doing to protect the user.”
This new theory also supports another idea surrounding Clovis points, which is that they’re very time-consuming to make and also more resource-intensive than typical arrowheads. This means it’s unlikely that an ancient hunter could want to waste such a resource on an attack method with a low success rate.
“Sometimes in archaeology,” Byram said, “the pieces just start fitting together like they seem to now with Clovis technology, and this puts pike hunting front and center with extinct megafauna. It opens up a whole new way of looking at how people lived among these incredible animals during much of human history.”
Although the strategy behind ancient humans’ megafauna hunting efforts appears to be coalescing, Byram and his team want to conduct a more realistic test involving a replica mammoth to simulate what would happen if a charging animal ran directly into this theorized pike system. However, because archaeologists only find Clovis points and not the accompanying weapon system, it's difficult to know for sure if such a system was used.
If it works as expected, we’ll need to rewrite our understanding of how indigenous peoples survived and thrived in the Americas 13,000 years ago and beyond.
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新定時技術有助於了解早期人類史 -- Aristos Georgiou
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Major' Archaeological Development May Help Rewrite Early Human History
Aristos Georgiou, 06/09/24
An innovative technique used in a study of Neanderthal hearths—places where fires were created—has been described by researchers as a "major" development in archaeology, one that could help shed light on prehistoric humans' behavior.
For a study published in the journal Nature, an interdisciplinary team of researchers found that a series of six Neanderthal hearths at El Salt, a Paleolithic site in Spain, were formed over at least 200 to 240 years, with each one likely having been created decades apart.
The findings are significant because determining the timescale of human activity in the Paleolithic period, also known as the Old Stone Age, has long been one of the most challenging problems in prehistoric archaeology. (This period in human prehistory extends from the earliest use of stone tools more than 3 million years ago to around 12,000 years ago.)
Resolving the timescale of such activity is difficult largely because of the limitations of dating techniques. For example, radiocarbon techniques cannot date samples that are older than around 50,000 to 60,000 years. Meanwhile, other techniques can produce errors of several thousand years.
Researcher Santiago Sossa-Ríos examines a hearth at El Salt, an archaeological site in Spain. Researchers have used an innovative technique to shed light on the chronology of six Neanderthal hearths at the site. SVEN KLEINHAPL/UNIVERSITY OF VALENCIA 請至原網頁觀看照片
"Although it has been proposed that Paleolithic hunter-gatherers were highly mobile, key aspects of their lifestyle, such as the time between camps and the size of traveling groups, remain unclear," the study's authors wrote. "Complexity in the formation of Paleolithic sites makes it difficult to single out human occupation episodes and resolve the time between them."
In the latest study, the research team—led by Ángela Herrejón-Lagunilla of Spain's University of Burgos—attempted to address this problem by examining hearths at El Salt, dated to around 52,000 years ago, with an innovative technique.
The technique involved a combination of "archaeostratigraphic" analyses—which helped the team determine the order the hearths were created in, based on their relative position in the ground layers—and an approach known as archaeomagnetic dating.
This technique studies and interprets signatures of the Earth's past magnetic field as recorded in burned archaeological remains. The approach works, given that burnt materials hold a record of the direction and/or intensity of the magnetic field at the time of the last fire.
The combination of the two approaches revealed that the Neanderthal hearths at El Salt were created decades or even up to a century apart—a finding that sheds light on the behavior of these early humans, who went extinct around 40,000 years ago. The results provide an indication of the timing of the hearths in unprecedented resolution.
"When we excavate archaeological settlement areas, we assume that they are the result of many events of human activity, but until now we did not know exactly how much time had passed between these activities. We did not know whether it was decades, centuries or thousands of years," said Santiago Sossa-Ríos, a researcher in prehistory, archaeology and ancient history at Spain's University of Valencia and an author on the study, in a press release.
"From there, within this temporary framework, we can open up new lines of investigation to study, for example, patterns of mobility, technological change or differences in the use of space," he continued. "The time is there, the challenge lies in combining and extracting everything that the methods offer us to uncover it."
Hearths can yield useful information about Neanderthal life because they are good indicators of occupation within a given site.
The new findings indicate that while Neanderthals were highly mobile, in some cases they may have returned to previous settlements after lengthy periods but still within the space of individual lifetimes.
In Paleolithic archaeology, a discipline in which human behavior is usually studied on long timescales typical of geological processes, being able to observe changes on timescales closer to a human lifespan is a significant development.
As a result, the techniques employed in the study could help to shed light on Paleolithic hunter-gatherers. They could even be applied to other archaeological contexts to resolve the timings of human activity.
"It is definitely a major step forward in archaeology, which will help us to better understand human behavior in the past," the study's authors said in the press release.
Aristos Georgiou is a Newsweek science reporter with the London, U.K., bureau. He reports on science and health topics, including; animal, mental health, and psychology-related stories. Aristos joined Newsweek in 2018 from IBTimes UK and had previously worked at The World Weekly. He is a graduate of the University of Nottingham and City University, London. Languages: English. You can get in touch with Aristos by emailing a.georgiou@newsweek.com.
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現代人和林德索人混血兒 ---- BENJAMIN TAUB
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How A Human-Neanderthal Hybrid Child Rewrote Human History
Our family tree is much messier than we thought.
BENJAMIN TAUB, Edited by Laura Simmons, 05/08/24
The Lapedo Child has a modern human jaw but Neanderthal limbs. Image credit: Microgen/Shutterstock.com (請至原網頁觀看相關照片)
Around 24,500 years ago, the body of a 4-year-old child was wrapped in an ochre-dyed shroud and lowered into a burial pit in the Lapedo Valley of central Portugal. Unlike any whippersnapper alive today, however, this extraordinary child exhibited a unique blend of modern human and Neanderthal features, disproving everything we thought we knew about the history of our species.
Known as the Lapedo Child, the youngster’s complete skeleton was discovered in 1998. Until then, anthropologists had assumed that modern humans evolved in East Africa before spreading across Eurasia and replacing the more archaic hominids that lived there – including Neanderthals.
This narrative supposed that we and our ancient relatives were completely separate species that could not interbreed, and that our expansion resulted in the extinction of our more primitive cousins. The Lapedo Child ripped up this script, prompting the discoverers to propose that modern humans did mate with Neanderthals, and that the genetic code of this extinct species persisted within the hybrid lineage that flowed from the loins of our cross-pollinating ancestors.
Thought to have been a male, the child himself possessed the chin and inner ear of an anatomically modern human, along with the stocky frame and limbs of a Neanderthal. Such a finding initially sent shockwaves through the anthropological world, sparking fierce debate as to what this all meant for human history.
In their original study on the skeleton, the authors note that the child lived several thousand years after Neanderthals had supposedly disappeared, suggesting that these ancestral traits must have been deeply ingrained within the human genome and that the young boy was therefore “the descendant of extensively admixed populations.” In other words, interbreeding between humans and Neanderthals didn’t just happen once or twice, but occurred on a population level, resulting in significant hybridization.
This, in turn, implies that Neanderthals didn’t simply die out when modern humans came along, but repeatedly hooked up with their new neighbours to the extent that they partially merged with them.
At the time of the discovery, this idea was seen as pretty radical and somewhat shocking, prompting some scholars to refute the original findings. One analysis, for instance, concluded that the Lapedo Child was not a hybrid after all but, was just an oddly-shaped modern human sprog.
However, the admixture theory was finally proven in 2010 when researchers sequenced the Neanderthal genome. In doing so, they revealed that all modern non-African populations contain between 1 and 4 percent Neanderthal DNA, thus confirming that our ancient ancestors did interbreed with these extinct hominids.
Thankfully, our phenotypes have straightened out somewhat over the millennia and we no longer possess the Neanderthal physique. However, like the Lapedo Child, those of us who hail from outside of Africa are all modern human-Neanderthal hybrids.
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現代日本人來源-Emily Cooke
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索引：
Jomon：繩文人
Yayoi people：彌生人
Modern Japanese people arose from 3 ancestral groups, 1 of them unknown, DNA study suggests
Emily Cooke, 04/18/24
Modern Japanese people largely originated from three ancestral groups and carry ancient DNA that may influence their risk of developing certain diseases, genetic analyses suggest.
A large new study has revealed new insight into the evolutionary history of Japanese people. (Image credit: Grant Faint via Getty Images) (請至原網頁參看照片)
Modern Japanese people largely descend from three ancestral groups, a new study suggests. The research also reveals genetic ties with our closest extinct relatives — the Neanderthals and Denisovans — and how these genes may affect present-day disease risk.
In one of the largest non-European analyses of its kind, scientists sequenced the DNA of more than 3,200 Japanese people across seven regions of the country, extending from the snowy mountains of Hokkaido in the north to the subtropical southern shores of Okinawa.
The researchers collated these genetic data, along with relevant clinical information, into a large new database called the Japanese Encyclopedia of Whole-Genome/Exome Sequencing Library (JEWEL).
The team discovered that modern Japanese people mostly descended from three ancestral groups: Neolithic Jomon hunter-gatherers; a group believed to have been the ancient predecessors of the Han Chinese; and an unidentified group with ties to Northeast Asia. This finding further challenges a contested, three-decades-long hypothesis that Japanese people originated from the Jomon people and, later, rice-farming Yayoi migrants from continental Asia.
The new analysis also revealed 42 pieces of DNA that Japanese people inherited from Neanderthals and two from Denisovans that could be linked to complex traits, meaning those that are encoded by multiple genes. This inheritance was likely the result of earlier interbreeding events between these ancient groups and early Homo sapiens, the authors wrote in the paper.
Denisovan-derived DNA within a gene called NKX6-1 was associated with the development of type 2 diabetes (T2D), and within the gene POLR3E, it was tied to height, the authors found. Eleven Neanderthal-derived DNA sequences were found to be associated with seven diseases, including T2D, coronary artery disease, prostate cancer and the inflammatory disorder rheumatoid arthritis. Most of these 44 chunks of ancient DNA are unique to East Asians, the authors said.
Until recently, large-scale genetic sequencing research has focused on analyzing DNA from people of European descent, leaving a significant gap in our understanding of other human populations, including those in Asia. Therefore, the new findings may provide some long-coveted answers.
"This comprehensive genetic dataset enables us to delve into uncharted territories concerning population and medical genetics of the Japanese population," the authors wrote in a paper describing their findings, published Wednesday (April 17) in the journal Science Advances.
These discoveries could even supplement research that could lead to the development of personalized medicine, the authors wrote.
For instance, the team identified gene mutations that could be clinically important within the Japanese population. One notable example is a mutation in a gene called PTPRD that was found in six people in the cohort. Clinical information was available for three of these individuals, who experienced several of the same health conditions, including having heart attacks, kidney failure and high blood pressure.
JEWEL will serve as a "reference for future genetic research within and beyond the Japanese population," the study authors concluded.
Emily Cooke is a health news writer based in London, United Kingdom. She holds a bachelor's degree in biology from Durham University and a master's degree in clinical and therapeutic neuroscience from Oxford University. She has worked in science communication, medical writing and as a local news reporter while undertaking journalism training. In 2018, she was named one of MHP Communications' 30 journalists to watch under 30. (emily.cooke@futurenet.com)
Related:
India's evolutionary past tied to huge migration 50,000 years ago and to now-extinct human relatives
Ancient bones reveal previously unknown Japanese ancestors
Freckled woman with high alcohol tolerance lived in Japan 3,800 years ago
Analysis of ancient teeth questions theory that Native Americans originated from Japan
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龍人與德尼索文人同源同種？ - Robin McKie
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根據DNA分析和發現的頭骨，人類學家認為：中國龍人(Homo longi)和德尼索文人很可能同源同種。
Scientists link elusive human group to 150,000-year-old Chinese ‘dragon man’
Researchers have found fresh evidence that may connect the mysterious Denisovans to the early human species Homo longi
Robin McKie, Science editor, 03/30/24
A preliminary portrait of a young woman from the Denisovans, early humans whom scientists know little about. Photograph: Maayan Harel (請至原網頁查看圖片)
They remain one of the most elusive groups of humans to have walked on earth. Evidence from the DNA traces left by Denisovans shows they lived on the Tibetan plateau, probably travelled to the Philippines and Laos in south Asia and might have made their way to northern China more than 100,000 years ago. They also interbred with modern humans.
What Denisovans looked like or how they lived has remained a mystery, however. Only a jaw fragment, a few bits of bone and one or two teeth provide any evidence of their physical characteristics.
Their DNA, which was first found in samples from the Denisova cave in Siberia in 2010, provides most of our information about their existence.
But recently scientists have pinpointed a strong candidate for the species to which the Denisovans might have belonged. This is Homo longi – or “Dragon man” – from Harbin in north-east China. This key fossil is made up of an almost complete skull with a braincase as big as a modern human’s and a flat face with delicate cheekbones. Dating suggests it is at least 150,000 years old.
“We now believe that the Denisovans were members of the Homo longi species,” said Prof Xijun Ni of the Chinese Academy of Sciences in Beijing, last week. “The latter is characterised by a broad nose, thick brow ridges over its eyes and large tooth sockets.”
The possible Denisovan-Homo longi link is one of several recent developments by researchers working on these humans with whom Homo sapiens shared the planet for hundreds of thousands of years. It is even thought they could have played a key role in our own evolution.
A reconstruction of the head of a young woman belonging to the Denisovan group of early humans based on a skeletal profile from DNA. Photograph: Maayan Harel (請至原網頁查看圖片)
Scientists in Tibet have discovered a Denisovan gene in local people, the result of interbreeding between the two species in the distant past. Crucially, this gene has been shown to help modern men and women survive at high altitudes.
In addition, evidence to support the Denisovan-Homo longi link has also been traced to the Tibetan plateau, where scientists began studying a jawbone initially found in a remote cave 3,000 metres (10,000ft) above sea level by a Buddhist monk, who kept it as a relic.
The bone was found not to come from a modern human. But only when researchers began to study the cave where the jawbone had been originally discovered did they find its sediments were rich in Denisovan DNA. In addition, it was found the fossil itself contained proteins that indicated Denisovan origins.
“It was the first time a Denisovan fossil find had been made outside Sibera and that was very important,” said Janet Kelso of the Max Planck Institute of Evolutionary Anthropology in Leipzig, Germany. “Equally intriguing was the fact that the jawbone has teeth that are similar to the teeth found in Homo longi. So I think the evidence suggests a link between the cranium and Denisovans”
This view was backed by Prof Chris Stringer of the Natural History Museum in London. “The evidence supports the idea that Denisovans were members of Homo longi but we are still short of absolute proof. Nevertheless, that will come with time, I believe.”
A big problem for researchers has been the fact that no DNA has yet been found in Chinese fossils such as Homo longi, added Stringer. “Their genes have not survived the passing of time. However, using the techniques of proteomics may provide key new data. These focus on a fossil’s proteins, which survive for far longer than its DNA and could tell us much more about the species.”
Recent research also suggests these people might have played a key role in the evolution of our own species.
The impact of the Denisovan gene found in Tibetans today provides one example. But Denisovan DNA has also been found in other modern populations, including people in New Guinea, northern Australia and the Philippines, and appears to have helped them fight infections from diseases such as malaria.
地圖顯示丹尼索文人種分佈地區 (請至原網頁查看圖片)
Denisovans settled in areas that covered a very varied geography, said Stringer. “Some were hot and low-lying, others were cold and mountainous. They represented very diverse habitats, from the Tibetan plateau to islands like Sulawesi [in Indonesia].”
By contrast, the Neanderthals, the third large grouping of humans that evolved over the past few hundreds of thousands of years, confined themselves to the cooler climates of a region that stretched east from Europe to southern Siberia.
They did not expand from this relatively uniform environment. So is the rich variety of homelands adopted by the Denisovans a sign that they were capable of much more diverse and adaptive behaviour than Neanderthals, scientists are now asking?
Homo sapiens also appears to have interbred with Denisovans on more than one occasion. “Indeed, there is good evidence that some modern humans interbred with genetically distinct Denisovans on multiple occasions,” said Kelso. “This suggests that the two groups coexisted for an extended time, with some studies suggesting a last contact as recently as 25,000 years ago.”
Crucially, by this time, Neanderthals were already extinct.
Research being carried out by Ni and Stringer also suggests that of the three main bands of humans who evolved at this time, Homo sapiens and the Homo longi group were the last to diverge on different evolutionary pathways, possibly a million years ago, with the Neanderthals branching off even earlier.
However, DNA analyses have suggested more recent divergence dates, with Homo sapiens splitting off first, so this is a crucial question for future research, said Stringer.
“How often our paths crossed after that parting of the ways is also now a topic of intense scientific interest,” he added. “We have got so much to learn.”
Related Reading：
Where did they all go? How Homo sapiens became the last human species left
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人類起源於何時？何地？ –--- Gemma Tarlach
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Where Did Humans Evolve? (Probably Not Where You’re Thinking)
For decades, East Africa was considered the birthplace of our species. Fossils from Morocco suggest otherwise.
GEMMA TARLACH, 02/22/24
DRIVE WEST ABOUT TWO HOURS from the vibrant souks of Marrakech and you will reach the small village of Tlet Ighoud. The rural community stretches along the intersection of two narrow, minor highways. If you follow one of them north for a couple miles, you’ll find an old pit from an abandoned mining operation.
In this arid region, the site’s tumble of red and orange rocks seems like nothing special, but it was here, more than 60 years ago, that miners uncovered what appeared to be a human skull. The find was the first of many from the site known as Jebel Irhoud. Collectively, the discoveries there have shaken up the story of our species, by challenging two of the most fundamental questions we can ask: When did we evolve and where did we come from?
For decades, those questions have been answered based on bones. But all of the early Homo sapiens fossils known to science could comfortably fit in your living room with space to spare. Most come from East African sites, such as northern Tanzania’s Ngaloba beds, or Omo Kibish, a collection of locations nestled in a remote Ethiopian river valley. Fossils from both of those locales, and others in East Africa, have been dated to between 120,000 and 200,000 years ago, and long represented what scientists thought was the earliest chapter in the story of H. sapiens. (In 2022, using a more refined dating method, researchers discovered that Omo I, a skull from Omo Kibish, is around 233,000 years old.) Working with that fossil evidence, it made sense to think that we had evolved in East Africa. After all, the region had also been home to several earlier members of our family tree, including celebrity fossil Lucy (the most famous example of Australopithecus afarensis, which lived around three million years ago).
The first skull fossil from Jebel Irhoud, found by a miner in the early 1960s, was initially thought to belong to a Neanderthal. RYAN SOMMA, CC BY-SA 2.0/WIKIMEDIA (請至原網頁觀看相關照片)
When miners unearthed that first skull from Jebel Irhoud in 1961, it was assumed to belong to a Neanderthal—modern humans’ closest evolutionary relative, H. neanderthalensis—who had lived some 40,000 years ago. Subsequent analysis suggested it was actually H. sapiens, and pushed the age of the skull back to about 160,000 years—much earlier in the human story, but still younger than several of the fossils found in East Africa. Our species evolved to walk and run long distances, so it would be no great feat for early humans to spread across Africa in the millennia after our birth in the east.
Then, in the early years of the 21st century, a new team of paleoanthropologists arrived at Jebel Irhoud. They picked over spots that had been chewed up by the mining operation, where the first fossils were found, but also began excavating new and previously undisturbed areas. They went back further in time as they dug. There, in those older layers of rock, they found additional skulls, other human bones, stone tools, and ribs of zebras and gazelles that show clear evidence of having been butchered for food.
Later came the biggest news of all: Using multiple methods, the team determined the finds were about 300,000 years old. The Jebel Irhoud fossils, which include skulls with distinctively modern human faces, were tens of thousands of years older than any human fossil found in East Africa.
The discovery, published in a series of papers and reactions in Nature in 2017, made headlines—and created controversy. Critics noted that while the facial features of the Jebel Irhoud skulls were remarkably modern, the overall shape of the skulls was longer and lower than the bubble-like, rounded braincase of modern humans. That difference, they argued, made a case that the Jebel Irhoud individuals were actually not H. sapiens, but might belong to an earlier species, such as H. antecessor, which lived about a million years ago in Spain.
A reconstruction of an early Homo sapiens skull from Jebel Irhoud shows strikingly modern facial features, but a braincase (in blue) that is less bubble-like than the rounded skull of our species today. PHILIPP GUNZ, CC-BY-SA 2.0/MPI EVA LEIPZIG (請至原網頁觀看相關照片)
The team behind the 2017 findings, led by paleoanthropologists from Germany’s Max Planck Institute for Evolutionary Anthropology, remained steadfast in their assessment of the Jebel Irhoud fossils as H. sapiens. But they were also the first to caution that Morocco should not be considered the birthplace of our species.
There are, after all, a few other very early fossils, such as a skull from Florisbad, South Africa, that is at least 260,000 years old. That skull resembles the Jebel Irhoud examples, found on the opposite side of the continent, and is also considered by some paleoanthropologists to belong to early H. sapiens. The only way both the Florisbad and Jebel Irhoud individuals could belong to our species is if humans evolved much earlier than we thought, which could put our true birthplace anywhere on the continent.
While exactly where and how the Jebel Irhoud humans fit into our origin story remains uncertain, their fossils have fueled a shift in how we view human evolution. Since 2017, more paleoanthropologists have moved away from the idea that we evolved fully in East Africa and then dispersed across the continent and beyond.
Today, more researchers embrace a Pan-African idea of human evolution, which hypothesizes that our species evolved across a wide geographic area as multiple populations mixed and mingled. That theory got a boost in 2023, when genomic research published in Nature concluded that humans evolved from two ancestral populations that occasionally interbred over hundreds of thousands of years.
It was beyond the scope of that 2023 paper to determine the geographic range of these ancestral populations, but the role geography plays in forming our ideas about human evolution is often overlooked. There are many regions of Africa where highly acidic soil or other environmental conditions make fossilization almost impossible — bones there break down before they can be preserved, erasing any evidence of our ancestors. In other areas, notably East Africa, paleoanthropologists have found early human fossils because, frankly, that’s where they went looking for them. (It’s a similar story in South Africa, home to several important fossils of multiple early human relatives and the boldly named Cradle of Humankind, which stakes the country’s claim, over East Africa, as our first home.)
But back to your living room, the one theoretically filled with every early H. sapiens fossil ever found: That’s still all we have from our earliest chapters. Interpreting them is like trying to read a version of Darwin’s On the Origin of Species that’s been printed without any vowels—or most of the consonants, for that matter. Understanding the true map and timeline of human evolution will require finding and analyzing many, many more fossils, and as well as the clues tucked into DNA from both living and ancient populations. We may never know exactly where and when the first human was born, but with every fossil found, the likeliest spot shifts in both time and place. The next big shift may be only one strike of a miner’s pickaxe away.
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