Post by cjm on Jul 13, 2016 16:41:46 GMT
How China Is Rewriting the Book on Human Origins
Fossil finds in China are challenging ideas about the evolution of modern humans and our closest relatives
...
Keen to get to the bottom of its people's ancestry, China has in the past decade stepped up its efforts to uncover evidence of early humans across the country. It is reanalysing old fossil finds and pouring tens of millions of dollars a year into excavations. And the government is setting up a $1.1-million laboratory at the IVPP to extract and sequence ancient DNA.
The investment comes at a time when palaeoanthropologists across the globe are starting to pay more attention to Asian fossils and how they relate to other early hominins — creatures that are more closely related to humans than to chimps. Finds in China and other parts of Asia have made it clear that a dazzling variety of Homo species once roamed the continent. And they are challenging conventional ideas about the evolutionary history of humanity.
“Many Western scientists tend to see Asian fossils and artefacts through the prism of what was happening in Africa and Europe,” says Wu. Those other continents have historically drawn more attention in studies of human evolution because of the antiquity of fossil finds there, and because they are closer to major palaeoanthropology research institutions, he says. “But it's increasingly clear that many Asian materials cannot fit into the traditional narrative of human evolution.”
...
Most Chinese palaeontologists — and a few ardent supporters from the West — think that the transitional fossils are evidence that Peking Man was an ancestor of modern Asian people. In this model, known as multiregionalism or continuity with hybridization, hominins descended from H. erectus in Asia interbred with incoming groups from Africa and other parts of Eurasia, and their progeny gave rise to the ancestors of modern east Asians, says Wu.
...
Some Western researchers suggest that there is a hint of nationalism in Chinese palaeontologists' support for continuity. “The Chinese — they do not accept the idea that H. sapiens evolved in Africa,” says one researcher. “They want everything to come from China.”
...
But the continuity-with-hybridization model is countered by overwhelming genetic data that point to Africa as the wellspring of modern humans. Studies of Chinese populations show that 97.4% of their genetic make-up is from ancestral modern humans from Africa, with the rest coming from extinct forms such as Neanderthals and Denisovans. “If there had been significant contributions from Chinese H. erectus, they would show up in the genetic data,” says Li Hui, a population geneticist at Fudan University in Shanghai. Wu counters that the genetic contribution from archaic hominins in China could have been missed because no DNA has yet been recovered from them.
...
A third idea is even more radical. It emerged when Martinón-Torres and her colleagues compared more than 5,000 fossil teeth from around the world: the team found that Eurasian specimens are more similar to each other than to African ones. That work and more recent interpretations of fossil skulls suggest that Eurasian hominins evolved separately from African ones for a long stretch of time. The researchers propose that the first hominins that left Africa 1.8 million years ago were the eventual source of modern humans. Their descendants mostly settled in the Middle East, where the climate was favourable, and then produced waves of transitional hominins that spread elsewhere. One Eurasian group went to Indonesia, another gave rise to Neanderthals and Denisovans, and a third ventured back into Africa and evolved into H. sapiens, which later spread throughout the world. In this model, modern humans evolved in Africa, but their immediate ancestor originated in the Middle East.
...
Despite the different interpretations of the Chinese fossil record, everybody agrees that the evolutionary tale in Asia is much more interesting than people appreciated before. But the details remain fuzzy, because so few researchers have excavated in Asia.
...
Fossil finds in China are challenging ideas about the evolution of modern humans and our closest relatives
...
Keen to get to the bottom of its people's ancestry, China has in the past decade stepped up its efforts to uncover evidence of early humans across the country. It is reanalysing old fossil finds and pouring tens of millions of dollars a year into excavations. And the government is setting up a $1.1-million laboratory at the IVPP to extract and sequence ancient DNA.
The investment comes at a time when palaeoanthropologists across the globe are starting to pay more attention to Asian fossils and how they relate to other early hominins — creatures that are more closely related to humans than to chimps. Finds in China and other parts of Asia have made it clear that a dazzling variety of Homo species once roamed the continent. And they are challenging conventional ideas about the evolutionary history of humanity.
“Many Western scientists tend to see Asian fossils and artefacts through the prism of what was happening in Africa and Europe,” says Wu. Those other continents have historically drawn more attention in studies of human evolution because of the antiquity of fossil finds there, and because they are closer to major palaeoanthropology research institutions, he says. “But it's increasingly clear that many Asian materials cannot fit into the traditional narrative of human evolution.”
...
Most Chinese palaeontologists — and a few ardent supporters from the West — think that the transitional fossils are evidence that Peking Man was an ancestor of modern Asian people. In this model, known as multiregionalism or continuity with hybridization, hominins descended from H. erectus in Asia interbred with incoming groups from Africa and other parts of Eurasia, and their progeny gave rise to the ancestors of modern east Asians, says Wu.
...
Some Western researchers suggest that there is a hint of nationalism in Chinese palaeontologists' support for continuity. “The Chinese — they do not accept the idea that H. sapiens evolved in Africa,” says one researcher. “They want everything to come from China.”
...
But the continuity-with-hybridization model is countered by overwhelming genetic data that point to Africa as the wellspring of modern humans. Studies of Chinese populations show that 97.4% of their genetic make-up is from ancestral modern humans from Africa, with the rest coming from extinct forms such as Neanderthals and Denisovans. “If there had been significant contributions from Chinese H. erectus, they would show up in the genetic data,” says Li Hui, a population geneticist at Fudan University in Shanghai. Wu counters that the genetic contribution from archaic hominins in China could have been missed because no DNA has yet been recovered from them.
...
A third idea is even more radical. It emerged when Martinón-Torres and her colleagues compared more than 5,000 fossil teeth from around the world: the team found that Eurasian specimens are more similar to each other than to African ones. That work and more recent interpretations of fossil skulls suggest that Eurasian hominins evolved separately from African ones for a long stretch of time. The researchers propose that the first hominins that left Africa 1.8 million years ago were the eventual source of modern humans. Their descendants mostly settled in the Middle East, where the climate was favourable, and then produced waves of transitional hominins that spread elsewhere. One Eurasian group went to Indonesia, another gave rise to Neanderthals and Denisovans, and a third ventured back into Africa and evolved into H. sapiens, which later spread throughout the world. In this model, modern humans evolved in Africa, but their immediate ancestor originated in the Middle East.
...
Despite the different interpretations of the Chinese fossil record, everybody agrees that the evolutionary tale in Asia is much more interesting than people appreciated before. But the details remain fuzzy, because so few researchers have excavated in Asia.
...