Cave of Denis, bounty of archaeological discovery
Michael Shunkov (front left) and Maxim Kozlikin (back right) — the main excavators at Denisova Cave, with Tom Higham in the centre and Katerina Douka back left.
The first issue of the journal Nature was published on November 4, 1869, costing fourpence. It has since been the standard bearer of scientific research, reflected in such iconic papers as "A structure for deoxyribose nucleic acid", published in 1953 — a paper that led to Crick and Watson's Nobel Prize for identifying the structure of DNA.
This past week has seen another notable article published, in Nature Communications, that describes the discovery of a new human species that was only possible because of the surviving ancient DNA in a tiny human finger bone.
The scene is Denisova cave in the remote Altai Mountains of Siberia. In the cave, once occupied by a monk called Denis, the cultural deposits go down metres in depth and thousands of years in time. Painstaking excavations by Russian archaeologists have traced the prehistoric occupation of the cave through the stone tools and fragments of bone — fragments because most had been crunched by hyaenas. The project was joined by international scientists, including my son Tom and his wife Katerina, both specialists in dating.
In 2008, a tiny finger bone found its way to the Max Plank Institute, in Leipzig, for DNA analysis and it turned the evolution of the human past on its head, for it came from a unknown species that the excavation team named Denisovan. This has led to a hunt for more Denisovan bones, made the more significant by the fact that modern people from Tibet to New Guinea count Denisovans among their ancestors.
There is a new analytical technique that can identify a bone fragment by extracting its collagen, and Tom and Katerina took bags of bone chips back to Oxford from Denisova Cave. After analysing more than 1000, their graduate student Samantha Brown struck gold: a fragment of human bone.
Off to Leipzig it went, followed by a long and anxious wait for the DNA results to come through. The stunning result was a world first: the bone came from a young girl whose mother was a Neanderthal, and father a Denisovan, who lived about 90,000 years ago. Not only was this unique discovery the world's first known human hybrid, but it featured on the front cover of Nature. Since then, the search for more Denisovans has reached the highlands of Tibet and tropical Laos and the seas off Taiwan. It seems Denisovans and Neanderthals once had a common ancestor about 390,000 years ago and placing both in the jigsaw of human evolution is continuing apace.
For the full story, read Tom Highams' The World Before Us: How Science is Revealing a New Story of Our Human Origins.
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Otago Daily Times
a day ago
- Otago Daily Times
Cave of Denis, bounty of archaeological discovery
Michael Shunkov (front left) and Maxim Kozlikin (back right) — the main excavators at Denisova Cave, with Tom Higham in the centre and Katerina Douka back left. The first issue of the journal Nature was published on November 4, 1869, costing fourpence. It has since been the standard bearer of scientific research, reflected in such iconic papers as "A structure for deoxyribose nucleic acid", published in 1953 — a paper that led to Crick and Watson's Nobel Prize for identifying the structure of DNA. This past week has seen another notable article published, in Nature Communications, that describes the discovery of a new human species that was only possible because of the surviving ancient DNA in a tiny human finger bone. The scene is Denisova cave in the remote Altai Mountains of Siberia. In the cave, once occupied by a monk called Denis, the cultural deposits go down metres in depth and thousands of years in time. Painstaking excavations by Russian archaeologists have traced the prehistoric occupation of the cave through the stone tools and fragments of bone — fragments because most had been crunched by hyaenas. The project was joined by international scientists, including my son Tom and his wife Katerina, both specialists in dating. In 2008, a tiny finger bone found its way to the Max Plank Institute, in Leipzig, for DNA analysis and it turned the evolution of the human past on its head, for it came from a unknown species that the excavation team named Denisovan. This has led to a hunt for more Denisovan bones, made the more significant by the fact that modern people from Tibet to New Guinea count Denisovans among their ancestors. There is a new analytical technique that can identify a bone fragment by extracting its collagen, and Tom and Katerina took bags of bone chips back to Oxford from Denisova Cave. After analysing more than 1000, their graduate student Samantha Brown struck gold: a fragment of human bone. Off to Leipzig it went, followed by a long and anxious wait for the DNA results to come through. The stunning result was a world first: the bone came from a young girl whose mother was a Neanderthal, and father a Denisovan, who lived about 90,000 years ago. Not only was this unique discovery the world's first known human hybrid, but it featured on the front cover of Nature. Since then, the search for more Denisovans has reached the highlands of Tibet and tropical Laos and the seas off Taiwan. It seems Denisovans and Neanderthals once had a common ancestor about 390,000 years ago and placing both in the jigsaw of human evolution is continuing apace. For the full story, read Tom Highams' The World Before Us: How Science is Revealing a New Story of Our Human Origins.
RNZ News
7 days ago
- RNZ News
A reservoir of gold lies hidden in Earth's core. Scientists say it's leaking
By Jacopo Prisco , CNN Gold and other precious metals deep beneath the Earth eventually make their way up to the surface during the formation of volcanic islands, a study suggests. Photo: 123rf Gold and other precious metals are leaking from Earth's core into the layers above, eventually making their way up to the surface during the formation of volcanic islands like Hawaii, a new study suggests. The theory results from a three-year analysis of Hawaii's basaltic rocks, which originally formed from plumes of magma, or molten rock, rising from the ocean floor. Clues in the form of heavy metals found in the volcanic rocks could confirm a suspicion long held by geologists - that Earth's molten core is not isolated but likely bleeds into the rocky mantle, the layer between the planet's thin crust and the core. "About 40 years ago, people first came up with the theory that maybe the core is losing some material into the mantle, but the signals we got so far were really ambiguous," said Nils Messling, a geochemist at the University of Göttingen in Germany and lead author of the report, published 21 May in the journal Nature . "Now, in my opinion, we have the first very strong evidence that some of the core is actually ending up in the mantle." Scientists already knew that most of the gold on the planet - more than 99.95 percent, according to Messling - lies hidden in the molten core, along with other heavy elements such as platinum. Basalt sampled from a drill core section from the Kilauea Iki lava lake, which erupted in 1959, is shown. The Hawaiian lava rock contains a small trace of Earth's core, the analysis found. Photo: Supplied / CNN / Nils Messling As meteorites bombarded one another in Earth's early history, a reservoir of these precious metals developed when the core formed about 4.5 billion years ago. But this study suggests that at least a tiny amount of that gold has escaped to the surface, raising the fascinating prospect that, if the leaking continues, more and more of this precious metal could travel from the centre of Earth to the crust in the future. "Our findings not only show that the Earth's core is not as isolated as previously assumed. We can now also prove that huge volumes of super-heated mantle material - several hundreds of quadrillion metric tonnes of rock - originate at the core-mantle boundary and rise to the Earth's surface to form ocean islands like Hawaii," said study coauthor Matthias Willbold, a professor at the University of Göttingen, in a statement. To find evidence of this core-mantle interaction, Messling and his coauthors obtained some samples of Hawaiian volcanic rocks from the Smithsonian Institution in Washington, DC. The research team extracts precious metals from samples of Hawaii's volcanic rock. Photo: Supplied / CNN / Nils Messling "Some were taken by a submarine, from a deep sea volcano, but [otherwise] it's basically just very ordinary-looking basaltic rock, very unassuming, that you would find anywhere on Hawaii," he said. "We started with half a kilogram of rock, we crushed it into a powder, and then we melted it in the oven with some different chemicals, to end up with a sample in liquid form." From that sample, the team extracted all the elements in the platinum group , which includes platinum itself as well as the lesser-known rhodium, palladium, iridium, osmium and ruthenium. The scientists then focused on ruthenium, a silver-grey metal about as rare in Earth's crust as gold. "The mantle has almost no ruthenium in it," Messling said. "It's one of the rarest elements on Earth. But Earth is basically made of meteorites that crashed together, and meteorites [contain] ruthenium, which went into the core when the core formed. So the mantle has next to no ruthenium, and the core has all of the ruthenium. The same with gold and platinum." Earth's core has two layers. A hot, solid metal sphere of iron and nickel is roughly 70 percent the size of the moon, with a radius of about 1221km. A liquid metal outer core is about 2253km thick and extends to about 2897km below the surface, or right up to the mantle. Photo: 123rf In contrast, the mantle, which lies between the planet's outer crust and the molten core, is 2897km of mostly solid rock. To determine whether the extracted ruthenium was originally from the core and not the mantle, the team looked at a specific isotope, or type, of ruthenium that was likely more abundant in Earth's early building materials during the time the core formed billions of years ago. "The vast majority of gold and other precious metals like platinum were likely delivered by massive meteorite impacts during the final stages of Earth's formation - a process known as late accretion," said Pedro Waterton, an assistant professor of geochemistry at the University of Copenhagen in Denmark who was not involved in the study. The presence of the ruthenium isotope in the basalt samples indicates that at least some of the rock was formed from material coming from the molten metallic core. That's because there is consensus, Messling said, that the material that coalesced during the early stages of Earth's formation does not exist in the meteorite record anymore. He added that the isotope signature in rocks from hotspot volcanoes like the ones in Hawaii is entirely different from any other known rock or meteorite. In other words, the ruthenium isotope Messling found was locked away in the core billions of years ago, so detecting the isotope in volcanic rocks today suggests it comes from the core. "It's quite a novel and difficult method," Messling said. "We managed to measure ruthenium in rocks that have next to no ruthenium in them. In half a kilo of rock, it was less than milligrams - a needle in a planet-sized haystack! That's quite exciting - for a geochemist, at least. It was a long but very exciting process." So what's the connection with gold? It's chemically similar to ruthenium, Messling said, so if the core is leaking ruthenium, it is also leaking gold in similar quantities. This would be a "minuscule" amount, however. And even if scientists wanted to extract gold directly from the source, the core-mantle boundary, that's much farther down than current technology could drill. In fact, it's about 236 times deeper than the deepest bore ever drilled - the Kola Superdeep Borehole in Russia, which reaches a depth of 12.3km. The ruthenium isotope signature in rocks from hotspot volcanoes like the ones in Hawaii is entirely different from any other rock or meteorite on record, according to lead study author Nils Messling. geochemist at the University of Göttingen. Photo: Supplied / CNN / Nils Messling Proof that the core isn't isolated is particularly thrilling because the core and the mantle shouldn't interact at all, Messling said. "Their density is too different, like oil and water, so technically they shouldn't mix. And we still don't have a good mechanism to explain why they do. We don't really know much about the core at all," he said. The Hawaiian rock samples suggest that the leaking process takes between 500 million and 1 billion years to complete, Messling said. "It's something that has occurred a while ago, and we suspect that it probably has been going on forever, and it's probably still occurring now," he explained. According to Messling, if the leaking of precious metals is an ongoing process, it could be that at least some of the gold humans have mined may have come from the core even if the quantity of core material in a single rock is negligible and that the world's supply of gold seems to be replenishing. "It's a very interesting idea that, although this process is tiny and has zero effect if you look at just one island, if you scale it up to 4.5 billion years it could be that it changes the composition of the Earth," he said. Researchers who were not involved in the study expressed positive views on the findings. "We know that the Earth was built from different generations of meteoritic material that were added progressively to the growing planet, and that precious metals from the earliest generations of meteorite material became concentrated into our planet's core while metals from meteorites added in the final stages of the Earth's growth became stranded in our planet's mantle," said Helen Williams, a professor of geochemistry and planetary science at the University of Cambridge in the United Kingdom. The study, she added, confirms that the mantle plumes - rising jets of molten rock coming from the core-mantle boundary that create hot spots like Hawaii - do indeed contain material somehow derived from Earth's metallic core, said Williams, adding that the result was "exciting." Jesse Reimink, an associate professor of geosciences at Pennsylvania State University, agrees. "This is a very old debate, and new data over the past 10 or so years has reinvigorated the possibility that the core was chemically 'leaking' into the mantle over time," he said. "This study really does seem to nail the conclusion - the core does contribute some material to the mantle." The latest research also strengthens the case made in previous work that some mantle plumes incorporate material from Earth's core, said the University of Copenhagen's Waterton. Does that also mean some of the gold in Earth's crust is originally from the core? "Yes, but probably only a very small amount," he said. - CNN
RNZ News
26-05-2025
- RNZ News
MPI closely watching bird flu vaccine trials for cattle and poultry
In December 2024 US authorities ordered a testing regimen for the nation's milk supply, amid increasing concerns over the H5N1 bird flu virus. Dairy cows in Ithaca, New York, on 11 December, 2024. Photo: AFP/ Michael M Santiago MPI says it's not currently doing research into high pathogenicity avian influenza vaccines for cattle but it is "closely" watching overseas trials for both cattle and poultry. The science journal Nature reported last week that US scientists were working on the first mRNA bird flu vaccine for cattle , using genetic code to help the body create antibodies to fight a disease, similar to the Covid-19 vaccine. Bird flu is already rife across US poultry and cattle farms but the researchers are racing to contain those outbreaks before they spark a human pandemic. Since March last year the H5N1 virus has infected more than a thousand dairy herds across 17 US states. MPI chief veterinary officer Dr Mary van Andel said MPI was following the US trial as well as other HPAI vaccine trials such as those in poultry. The commercial use of any vaccine for HPAI would need to be considered against the risks posed to the industry, and only after consultation with the affected industry, she added. "All vaccines for use in animals must be registered under the Agricultural Compounds and Veterinary Medicines (ACVM) Act before they can be imported to or manufactured, sold, or used in New Zealand. Similarly, vaccine trials conducted in New Zealand would also require ACVM authorisation before it can proceed. If a vaccine is needed to manage disease in New Zealand in future, either trial work to develop a new vaccine or registration of a vaccine available overseas are both options for consideration." It was important to remember that New Zealand had never had a case of the bird flu strain H5N1 2.3.4.4b, and that HPAI was not a cattle disease, she said. "The H5N1 strain of HPAI was detected in dairy herds in the United States following a spillover event in 2024. The US is the only country that has reported spillover to cattle worldwide, despite large seasonal outbreaks of this strain in other northern hemisphere countries." A different strain of avian influenza, H7N6, was detected at a north Otago egg farm in December. About 200,000 chickens were culled across five sites after the outbreak. Van Andel said MPI was working closely with international colleagues to learn everything it could from their experiences of H5N1 and it was keeping its industry partners informed. "We are closely monitoring updates from both the United States Department of Agriculture (USDA) and the Centers for Disease Control and Prevention (CDC), as well as keeping in regular contact with the US Chief Veterinary Officer. Our industry and scientific communities have close linkages with colleagues in the US." The CDC believed the current risk to the general public from bird flu viruses was low, she added. However people with job-related or recreational exposure to infected birds or animals, including cows, were at greater risk of contracting H5N1. "A small number of dairy farmworkers who were in close contact with infected cattle have been infected with the virus. These workers showed mild symptoms and recovered. HPAI H5N1 has not been detected or reported in beef cattle to date." Van Andel said that if the strain of HPAI did arrive in New Zealand, the risk of transmission from birds to cattle or other livestock was low. "We are working closely with the Department of Conservation, Health New Zealand Te Whatu Ora, the Ministry of Health and our industry partners to ensure we are ready should HPAI H5N1 be detected here. A key focus of this work is ensuring strong on-farm biosecurity practices are in place across the poultry industry and wider farming sector." MPI has worked with industry groups to develop advice and guidance for both commercial poultry farmers and dairy and other livestock farmers:
