As our world continues to warm up, vast areas of permafrost are rapidly melting, releasing material that’s been trapped for up to a million years. This includes uncountable numbers of microbes that have been lying dormant for hundreds of millennia.
To study these emerging microbes, scientists from the French National Center for Scientific Research have now revived a number of these “zombie viruses” from the Siberian permafrost, including one thought to be nearly 50,000 years old – a record age for a frozen virus returning to a state capable of infecting other organisms.
The team behind the study, led by microbiologist Jean-Marie, says these ancient viruses are potentially a significant threat to public health, and further study needs to be done to assess the danger that these infectious agents could pose as the permafrost melts.
The researchers warned it may just be the tip of the iceberg:
“One-quarter of the Northern Hemisphere is underlain by permanently frozen ground, referred to as permafrost,” researchers wrote in the paper.
“Due to climate warming, irreversibly thawing permafrost is releasing organic matter frozen for up to a million years, most of which decomposes into carbon dioxide and methane, further enhancing the greenhouse effect. Part of this organic matter also consists of revived cellular microbes (prokaryotes, unicellular eukaryotes) as well as viruses that remained dormant since prehistorical times.”
According to Global News:
In 2014, the same researchers unearthed a 30,000-year-old virus trapped in permafrost, the BBC reported. The discovery was groundbreaking because after all that time, the virus was still able to infect organisms. But now, they’ve beaten their own record by reviving a virus that is 48,500 years old.
“If the authors are indeed isolating live viruses from ancient permafrost, it is likely that the even smaller, simpler mammalian viruses would also survive frozen for eons,” virologist Eric Delwart from the University of California, San Francisco told New Scientist.
The world’s oldest known frozen and dormant virus has been revived in a French laboratory leading many to express concerns about the dangers of bringing to life ancient microbes. The virus was removed from the Siberian permafrost in Russia’s far east and is 48,500 years old, offering proof that viruses are incredibly hardy and capable of surviving indefinitely when they’re preserved in a frozen state.
Melting Siberian Permafrost in a Virus-Filled Pandora’s Box
This particular virus is actually one of nine different types of viruses that have been resuscitated from Siberian permafrost samples in recent years. That includes seven viruses resuscitated for this new study, and two other approximately 30,000-year-old viruses brought back to life by the same team of researchers from other samples taken in 2013. The youngest of these viruses was frozen 27,000 years ago.
As reported in the non-peer-reviewed journal bioRxiv, the 48,500-year-old virus has been named Pandoravirus yedoma , in reference to Pandora’s box. The virus was found in a sample of permafrost taken from 52 feet (16 m) below the bottom of a lake in Yukechi Alas in the Russian Republic of Yakutia.
The first-ever pandoravirus was one of the two viruses found in 2013, although that one was of a different type altogether. “48,500 years is a world record,” Jean-Michel Claverie, a virologist at Aix-Marseille University in France and the lead author of the permafrost viral study, told the New Scientist .
In addition to its age, the other remarkable feature of this pandoravirus is its size. Classified as a type of giant virus, Pandoravirus yedoma is approximately one micrometer long and .5 micrometers wide. This means they can be examined directly under a microscope. It contains approximately 2,500 genes, in contrast to the miniscule modern viruses that infect humans that possess no more than 10 to 20 genes.
Climate change and the resulting thawing of the permafrost could release a mass of new Siberian viruses into the atmosphere. ( Андрей Михайлов / Adobe Stock)
Climate Change and the Threat of Permafrost Viral Release
Given the disturbing coronavirus pandemic the world has just experienced, it might seem alarming that these scientists are intentionally reviving long-lost viruses previously hidden in the frozen wastelands of Siberia. But they say this research is necessary to evaluate the dangers associated with climate change.
“One quarter of the Northern Hemisphere is underlain by permanently frozen ground, referred to as permafrost,” they wrote in their newly published paper. With the thawing of the permafrost, organic matter which has been frozen for as many as a million years is thawing out. One of the effects of this is the release of carbon dioxide and methane into the atmosphere, amplifying the greenhouse effect.
The other is that “part of this organic matter also consists of revived cellular microbes (prokaryotes, unicellular eukaryotes) as well as viruses that remained dormant since prehistorical times,” explained the authors in bioRxiv. Only by extracting viruses from permafrost samples and reviving them in controlled conditions, the scientists claim, will it be possible to evaluate the nature of the threat they might pose to human health and safety in a warmer, permafrost-free future.
Since permafrost covers more one-fourth of all land territory in the Northern Hemisphere, this is not an idle concern. The viral load currently locked up in permanently frozen ground is undoubtedly massive, and if it were all released over the course of a couple of decades it could conceivably set off an avalanche of new viral infections in a variety of host species.
None of these victims would be immune to the impact of viral agents that had been out of circulation for tens of thousands of years. Immune systems would eventually adjust, but that might happen too late to prevent a catastrophic loss of life that cuts across the microbial-, plant- and animal-life spectrums.
The 48,500-year-old Siberian virus is a pandoravirus, which infects single-cell organisms known as amoebas. (Claverie et. al / bioRxiv)
Immortal Viruses May Be Returning Soon, in Quantities too Astounding to Imagine
Concerns about permafrost melting are not only theoretical. The once-frozen ground has already started to thaw in some areas, and that has allowed scientists to recover frozen and well-preserved specimens of animals that lived during the Paleolithic period.
In recent years the remains of wooly rhinos that went extinct 14,000 years ago have been found, and in one instance scientists recovered a 40,000-year-old wolf’s head that was in almost pristine condition. Wooly mammoth remains have proven especially easy to find in the freshly-thawed soil, so much so that a black-market industry has arisen in which mammoth tusks removed from illicitly unearthed mammoth skeletons are being sold to ivory traders.
What concerns scientists about this development is that potent infectious agents may be hiding dormant inside these well-preserved ancient animal remains. It is notable that the 27,000-year-old virus found in this new study was not removed from the lake bottom sample, but was instead extracted from frozen mammoth excrement taken from a different permafrost core.
Needless to say, ancient viruses released from thawed animal hosts would be more likely to evolve into something threatening to humans than a virus that specifically attacks microbes like amoeba.
Winter landscape and frozen lake in Yakutia, Siberia. ( Tatiana Gasich / Adobe Stock)
The Hidden Danger of Ancient Bacteria and Viruses in the Thawing Permafrost
In their research paper, Professor Claverie and his colleagues emphasized how dangerous ancient bacteria and viruses could be to present-day life forms of all types. Even if frozen in deeper levels of permafrost for millions of years, they could become active again should the permafrost disappear.
In comparison to outbreaks from modern viruses, “the situation would be much more disastrous in the case of plant, animal, or human diseases caused by the revival of an ancient unknown virus,” the French scientists wrote. “As unfortunately well documented by recent (and ongoing) pandemics, each new virus, even related to known families, almost always requires the development of highly specific medical responses, such as new antivirals or vaccines.”
The Arctic regions of the planet are largely free of permanent human settlers. But the researchers point out that more people are visiting the planet’s coldest regions than ever before, mainly to harvest valuable resources like oil, gold and diamonds that are present in abundance in these previously under-explored areas. In strip-mining operations the upper layers of the permafrost are actually torn out intentionally, meaning that viral exposures during such operations may be unavoidable.
“How long these viruses could remain infectious once exposed to outdoor conditions (UV light, oxygen, heat), and how likely they will be to encounter and infect a suitable host in the interval, is yet impossible to estimate,” the scientists concluded. “But the risk is bound to increase in the context of global warming when permafrost thawing will keep accelerating, and more people will be populating the Arctic in the wake of industrial ventures.”
Other scientists have warned of the dangers of viruses being released in the Arctic through the melting of glaciers, which is yet another possible side effect of global warming. This could expose animals and humans to flowing rivers of glacial meltwater that could carry pathogens to new areas further south.
Whether any of these worst-case scenarios come to fruition remains to be seen. But even a small amount of melting, regardless of the cause, could be enough to release some potentially hazardous viral agents into the global environment, where billions of vulnerable people live.
Top image: Colony of microbes, representational image. Source: iarhei / Adobe Stock
Oct 23 (Reuters) – A Russian military jet crashed into a residential building in the Siberian city of Irkutsk on Sunday and the two pilots were killed, officials said, the second such fatal incident in six days involving a Sukhoi fighter plane.
In a post on Telegram, Irkutsk governor Igor Kobzev said the plane crashed into a two-storey house in the city. He published a video showing firefighters clambering over the wreckage and directing jets of water at the still smouldering rubble.
No one on the ground was hurt, the governor said.
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Officials said the plane was a Sukhoi Su-30 fighter on a test flight. Last Monday, a Sukhoi Su-34 crashed into an apartment block in the southern city of Yeysk, near Ukraine, and at least 15 people were killed.
Videos of Sunday’s incident, shared on social media, showed the plane dived almost vertically before crashing in a fireball, sending dense black smoke into the sky.
Russia’s state Investigative Committee said it had launched a criminal investigation into violations of air safety rules.
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Reporting by Jake Cordell and Mark Trevelyan, Editing by William Maclean
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Remains of three Denisovans and one Neanderthal dating back 200,000 years have been uncovered in a Siberian cave, experts reveal.
The newly-found fossils were uncovered from the famous Denisova Cave in the Altai Mountains, southern Siberia, surrounded by archaeological remains such as stone tools and fossilised food waste.
Neanderthals were a close human ancestor that lived in Europe and Western Asia from about 400,000 to 40,000 years ago.
Less is known about the Denisovans, another population of early humans who lived in Asia at least 80,000 years ago and were distantly related to Neanderthals.
Dating to 200,000 years ago, the new Denisovan bones are some of the oldest human fossils to have ever been genetically sequenced.
The fact that the remains of both Neanderthals and Denisovans were found together raises questions about whether the two archaic human types lived there.
Bone fragments taken from the cave that were used for molecular analysis. The analysis revealed three bone fragments as Denisovan and one as Neanderthal
NEANDERTHALS AND DENISOVANS
Neanderthals were very early (archaic) humans who lived in Europe and Western Asia from about 400,000 years ago until they became extinct about 40,000 years ago.
Denisovans are another population of early humans who lived in Asia and were distantly related to Neanderthals.
Much less is known about the Denisovans because scientists have uncovered fewer fossils of these ancient people.
The precise way that modern humans, Neanderthals, and Denisovans are related is still under study.
However, research has shown that modern humans overlapped with Neanderthal and Denisovan populations for a period, and that they had children together (interbred).
As a result, many people living today have a small amount of genetic material from these distant ancestors.
Source: National Institutes of Health
It’s already known that Denisovans diverged from Neanderthals. Both also bred with humans around 50,000 years ago, meaning the DNA of the early hominids survives today.
The new findings are detailed in Nature Ecology and Evolution by an international team, led by researchers from the Universities of Vienna and Tübingen, and the Max Planck Society in Munich, Germany.
In all, five hominin bones were found in the cave, including four that had enough DNA for mitochondrial analysis and identification – three as Denisovan and one as Neanderthal.
‘Finding one new human bone would have been cool, but five? This exceeded my wildest dreams,’ said study author Samantha Brown at the University of Tübingen.
‘Denisovans are one of our most recent ancestors, and many people today still carry a small percentage of Denisovan DNA,’ Brown told USA Today, but she noted that there is still ‘very little information’ about this group.
Denisovans are thought to have appeared at the site during an interglacial – a warm period during which the environment and temperatures were similar to today.
It seems they had a ‘fully-fledged lithic tradition’, making use of raw material found in the alluvium of the nearby Anui River and hunting herbivores, such as bison, roe and red deer, gazelle and saiga antelope, and even woolly rhinoceros.
Around 130,000 to 150,000 years ago, Neanderthals also appeared at the site, represented by the one newly-discovered Neanderthal fossil.
The remains were discovered at the Denisova Cave (entrance pictured here) in the Altai Mountains, southern Siberia
FILIPINO ETHNIC GROUP HAVE THE MOST DENISOVAN DNA, STUDY FINDS
Modern-day people in the Philippines have the most Denisovan DNA in the world, a 2021 study found.
Researchers in Sweden have found that the Philippine Negrito ethnic group known as the Ayta Magbukon have the highest level of Denisovan ancestry today.
The Ayta Magbukon people, who occupy the Philippines’ Bataan Peninsula, have more Denisovan DNA than the Papuan Highlanders, who were previously known as the present-day population with the highest level of Denisovan ancestry.
Read more: Ayta Magbukon people have most Denisovan DNA in the world
Denisova Cave rose to fame 11 years ago, when genetic sequencing of a fossilised finger bone revealed a new, previously unknown human group – named ‘Denisovans’, in honour of the site.
But identifying further Denisovan remains at the cave has been challenging, as any human remains are fragmented and difficult to spot amongst hundreds of thousands of animal bones also present.
Over the course of four years, a team led by anthropologist Katerina Douka at the University of Vienna worked to extract and analyse ancient proteins and DNA from nearly 4,000 bone fragments from Denisova Cave.
The scientists used a biomolecular method known as peptide fingerprinting or ‘ZooMS’ – which uses collagen or other proteins preserved in archaeological artefacts to identify the species from which they derive.
Such methods are the only means by which scientists could find human remains among the thousands of bones from the site, as more than 95 per cent were too fragmented for standard identification methods.
The team focused on Denisova Cave’s oldest layers, which date to as early as 200,000 years ago.
Brown analysed 3,800 bone fragments no larger than 1.5 inches in length that were previously deemed ‘taxonomically unidentifiable’.
However, she finally identified five bones whose collagen matched the peptide profile of humans.
‘We were stunned to discover new human bone fragments preserving intact biomolecules from such ancient layers,’ said Douka.
Research at Denisova Cave continues through fieldwork and targeted analyses of bones and sediments with a team of Russian archaeologists camped there for nearly six months each year.
Excavations in the eastern chamber of Denisova Cave. The cave rose to fame 11 years ago, when genetic sequencing of a fossilised finger bone revealed a new, previously unknown human group – the Denisovans
Denisova Cave remains the only site so far discovered which contains evidence for the periodic presence of all three major hominin groups, Denisovans, Neanderthals and modern humans, in the last 200,000 years.
Earlier this year, scientists reported that DNA discovered in Denisova Cave suggests early modern humans lived alongside Denisovans and Neanderthals at least 44,000 years ago.
Last October, another team reported the discovery of Denisovan DNA in the Baishiya Karst Cave in Tibet.
This discovery marked the first time Denisovan DNA has been recovered from a location that is outside Denisova Cave in Siberia, Russia.
In August 2020, researchers revealed that DNA from an unknown ancient ancestor of humans that bred with Denisovans is still around today.
THE DENISOVANS EXPLAINED
Who were they?
The Denisovans are an extinct species of human that appear to have lived in Siberia and even down as far as southeast Asia.
The individuals belonged to a genetically distinct group of humans that were distantly related to Neanderthals but even more distantly related to us.
Although remains of these mysterious early humans have mostly been discovered at the Denisova Cave in the Altai Mountains in Siberia, DNA analysis has shown the ancient people were widespread across Asia.
Scientists were able to analyse DNA from a tooth and from a finger bone excavated in the Denisova cave in southern Siberia.
The discovery was described as ‘nothing short of sensational.’
In 2020, scientists reported Denisovan DNA in the Baishiya Karst Cave in Tibet.
This discovery marked the first time Denisovan DNA had been recovered from a location that is outside Denisova Cave.
How widespread were they?
Researchers are now beginning to find out just how big a part they played in our history.
DNA from these early humans has been found in the genomes of modern humans over a wide area of Asia, suggesting they once covered a vast range.
They are thought to have been a sister species of the Neanderthals, who lived in western Asia and Europe at around the same time.
The two species appear to have separated from a common ancestor around 200,000 years ago, while they split from the modern human Homo sapien lineage around 600,000 years ago.
Last year researchers even claimed they could have been the first to reach Australia.
Aboriginal people in Australia contain both Neanderthal DNA, as do most humans, and Denisovan DNA.
This latter genetic trace is present in Aboriginal people at the present day in much greater quantities than any other people around the world.
How advanced were they?
Bone and ivory beads found in the Denisova Cave were discovered in the same sediment layers as the Denisovan fossils, leading to suggestions they had sophisticated tools and jewellery.
Professor Chris Stringer, an anthropologist at the Natural History Museum in London, said: ‘Layer 11 in the cave contained a Denisovan girl’s fingerbone near the bottom but worked bone and ivory artefacts higher up, suggesting that the Denisovans could have made the kind of tools normally associated with modern humans.
‘However, direct dating work by the Oxford Radiocarbon Unit reported at the ESHE meeting suggests the Denisovan fossil is more than 50,000 years old, while the oldest ‘advanced’ artefacts are about 45,000 years old, a date which matches the appearance of modern humans elsewhere in Siberia.’
Did they breed with other species?
Yes. Today, around 5 per cent of the DNA of some Australasians – particularly people from Papua New Guinea – is Denisovans.
Now, researchers have found two distinct modern human genomes – one from Oceania and another from East Asia – both have distinct Denisovan ancestry.
The genomes are also completely different, suggesting there were at least two separate waves of prehistoric intermingling between 200,000 and 50,000 years ago.
Researchers already knew people living today on islands in the South Pacific have Denisovan ancestry.
But what they did not expect to find was individuals from East Asia carry a uniquely different type.
The entrance to Denisova Cave in Sibera. Image: IAET, Siberian Branch Russian Academy of Sciences
The Denisovans, a mysterious group of extinct hominins closely related to Neanderthals, didn’t leave much fossil evidence behind. A fresh dig at their former stomping grounds in Siberia has now yielded three new fossils—the oldest yet found of this species.
Katerina Douka, an evolutionary anthropologist from the University of Vienna, and her colleagues found the fossils in Denisova Cave, a natural shelter located in the Altai Mountains of southern Siberia. The scientists were studying the oldest layers in the cave, which up until now had failed to produce a single human fossil. A total of five human fossil fragments were recovered: three belonging to Denisovans, one from a Neanderthal, and one that could not be identified. The largest of these fragments measures no larger than 1.6 inches (4 centimeters) long.
Remarkably, this small but precious handful of fossils were found amid a jumble of 3,791 animal bone fragments. The researchers used a biomolecular method known as peptide fingerprinting to identify the bones, as it was not possible to do so through manual inspection. The five bones contained collagen consistent with the peptide profiles of humans (peptides are the building blocks of proteins), allowing for the identification (as a reminder, Denisovans and Neanderthals are humans).
Some of the bone fragments recovered in Denisova Cave. Image: S. Brown
“Finding one new human bone would have been cool, but five? This exceeded my wildest dreams,” Samantha Brown, a co-author of the study and junior group leader at the University of Tübingen, said in a Max Planck Institute statement.
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Denisova Cave is an “amazing place” when it comes to the preservation of DNA, and “we have now reconstructed genomes from some of the oldest and best-preserved human fossils,” said Diyendo Massilani, a geneticist from the Max Planck Institute of Evolutionary Anthropology, in the release. The team found enough DNA to reconstruct mitochondrial genomes, allowing them to confirm the bones as belonging to Denisovans and Neanderthals. A paper detailing this discovery has been published in Nature Ecology & Evolution.
The layer containing the Denisovan bones was dated to roughly 200,000 years old. Previous Denisovan fossils were dated to between 122,000 and 194,000 years old, so these are now the oldest. The lone Neanderthal bone was dated to between 130,000 and 150,000 years ago. The Altai mountains appear to “be an overlapping zone for both Denisovan and Neanderthal groups for over 150,000 years, witnessing and possibly facilitating population [interbreeding] as well as sustaining distinct hominin populations over this long period,” according to the paper.
The three new Denisovan fossils add to the six already discovered, including a finger bone from which DNA was extracted and a mandible found in a cave on the Tibetan Plateau—the first and only Denisovan fossil found outside of Siberia. Denisovans were closely related to Neanderthals, and they interbred with modern humans prior to going extinct some 50,000 to 30,000 years ago. Traces of Denisovan DNA exist within the genomes of modern southeast Asian and Oceanian populations.
As the scientists write in their study, “a wealth of archaeological material” in the form of stone tools and animal remains were found within the Denisovan layer. It’s the first time that archaeological evidence has been definitively linked to these hominins, allowing for new insights into their behavior.
Interestingly, the style of the recovered stone tools, like scraping tools for working animal hides, could not be matched to any known lithic tradition. Living near the Anui river and occupying the caves during a warm period, the Denisovans hunted bison, deer, gazelle, antelope, and woolly rhinos, in a subsistence pattern that lasted for thousands of years, as the researchers point out.
These three Denisovan bones will likely produce more science in the years to come, as will Denisova Cave in general. Slowly but very methodically, we’re uncovering more about these remarkable humans.
More: Scientists Have Discovered a Hotspot of Denisovan Ancestors.
The regional Investigative Committee said three people, including the director of the Listvyazhnaya mine and his deputy, had been arrested on suspicion of violating industrial safety rules.
It said miners had suffocated when a ventilation shaft became filled with gas. State television said prosecutors believed there had been a methane explosion.
The dead comprised 11 miners already confirmed killed, 35 who had been reported missing, and the six rescue workers.
Dozens of people were treated in hospital, at least some of them for smoke inhalation. Four were in critical condition.
The coal-producing region of Kemerovo, roughly 3,500 km (2,200 miles) east of Moscow, has suffered fatal mining accidents for years.
The Listvyazhnaya mine is part of SDS-Holding, owned by the privately held Siberian Business Union. The owner had no immediate comment.
Some 285 people were inside the mine when smoke spread through the ventilation shaft, the Emergencies Ministry said. Authorities said 239 had made it to the surface.
President Vladimir Putin said he had spoken with the governor and emergency officials, and the Kremlin said he had ordered the emergencies minister to fly to the region to help.
Kemerovo declared three days of mourning.
In 2007, the region was the site of the worst mining accident since the collapse of the Soviet Union when an explosion at the Ulyanovskaya mine claimed the lives of more than 100 people. In 2010, explosions at the region’s Raspadskaya mine killed more than 90 people.
Russian officials say 52 miners and rescuers have died after a devastating blast in a Siberian coal mine about 250 meters (820 feet) underground
By DARIA LITVINOVA and VLADIMIR ISACHENKOV Associated Press
November 25, 2021, 9:16 PM
• 3 min read
MOSCOW — A devastating explosion in a Siberian coal mine Thursday left 52 miners and rescuers dead about 250 meters (820 feet) underground, Russian officials said.
Hours after a methane gas explosion and fire filled the mine with toxic fumes, rescuers found 14 bodies but then were forced to halt the search for 38 others because of a buildup of methane and carbon monoxide gas from the fire. Another 239 people were rescued.
The state Tass and RIA-Novosti news agencies cited emergency officials as saying that there was no chance of finding any more survivors in the Listvyazhnaya mine, in the Kemerovo region of southwestern Siberia.
The Interfax news agency cited a representative of the regional administration who also put the death toll from Thursday’s accident at 52, saying they died of carbon monoxide poisoning.
It was the deadliest mine accident in Russia since 2010, when two methane explosions and a fire killed 91 people at the Raspadskaya mine in the same Kemerovo region.
A total of 285 people were in the Listvyazhnaya mine early Thursday when the blast sent smoke that quickly filled the mine through the ventilation system. Rescuers led to the surface 239 miners, 49 of whom were injured, and found 11 bodies.
Later in the day, six rescuers also died while searching for others trapped in a remote section of the mine, the news reports said.
Regional officials declared three days of mourning.
Russia’s Deputy Prosecutor General Dmitry Demeshin told reporters that the fire most likely resulted from a methane explosion caused by a spark.
The miners who survived described their shock after reaching the surface.
“Impact. Air. Dust. And then, we smelled gas and just started walking out, as many as we could,” one of the rescued miners, Sergey Golubin, said in televised remarks. “We didn’t even realize what happened at first and took some gas in.”
Another miner, Rustam Chebelkov, recalled the dramatic moment when he was rescued along with his comrades as chaos engulfed the mine.
“I was crawling and then I felt them grabbing me,” he said. “I reached my arms out to them, they couldn’t see me, the visibility was bad. They grabbed me and pulled me out, if not for them, we’d be dead.”
Explosions of methane released from coal beds during mining are rare but they cause the most fatalities in the coal mining industry.
The Interfax news agency reported that miners have oxygen supplies normally lasting for six hours that could only be stretched for a few more hours.
Russia’s Investigative Committee has launched a criminal probe into the fire over violations of safety regulations that led to deaths. It said the mine director and two senior managers were detained.
President Vladimir Putin extended his condolences to the families of the dead and ordered the government to offer all necessary assistance to those injured.
Thursday’s fire wasn’t the first deadly accident at the Listvyazhnaya mine. In 2004, a methane explosion left 13 miners dead.
In 2007, a methane explosion at the Ulyanovskaya mine in the Kemerovo region killed 110 miners in the deadliest mine accident since Soviet times.
In 2016, 36 miners were killed in a series of methane explosions in a coal mine in Russia’s far north. In the wake of the incident, authorities analyzed the safety of the country’s 58 coal mines and declared 20 of them, or 34%, potentially unsafe.
The Listvyazhnaya mine wasn’t among them at the time, according to media reports.
Russia’s state technology and ecology watchdog, Rostekhnadzor, inspected the mine in April and registered 139 violations, including breaching fire safety regulations.
Researchers have sequenced the oldest known DNA in the world. Using material from the Early and Middle Pleistocene sub-epochs, the ancient DNA analysis shatters the record for the world’s oldest sequenced DNA. It comes from mammoth remains that were discovered in the Siberian permafrost and proves that under the right conditions ancient DNA can survive more than one million years.
But the analysis of that very ancient DNA depends upon researchers having the right technology too. Thankfully, an international team led by researchers at the Centre for Palaeogenetics in Stockholm, Sweden had advanced sequencing technology and bioinformatics available to them. A Nature news report for the new paper says that the researchers pushed current technology almost to its limits to enable the extraction of ancient DNA strands from mammoth teeth that had been preserved in the Siberian permafrost . Senior author of the Nature study, Love Dalén, a professor of evolutionary genetics at the Centre for Palaeogenetics, notes that the scientific team has been lucky, saying:
“It’s not like everything found in the permafrost always works. The vast majority of samples have crap DNA.”
How the Ancient Mammoth DNA has Broken Records
The discovery is truly amazing because after an organism dies its chromosomes gradually become smaller and smaller, and in most cases extremely ancient DNA strands have become so tiny that they have lost all their informational content. But a new article published in the journal Nature shows that the team has managed to obtain 49 million base pairs of nuclear DNA from a 1.65-million-year-old tooth found near a village called Krestovka (the tooth has been dubbed Krestovka as well). They also extracted 884 million base pairs of ancient DNA from a 1.3-million-year-old tooth they refer to as Adycha and 3.7 billion base pairs of DNA from a 600,000-year-old woolly mammoth tooth they’ve called Chukochya. The three mammoth remains were discovered in the 1970s and are part of the collection of the Russian Academy of Sciences in Moscow.
Love Dalén and co-lead author Patrícia Pečnerová with a mammoth tusk on Wrangel Island. (Credit: Gleb Danilov)
The Nature news report explains that the ancient mammoth DNA study hasn’t uncovered the oldest biomolecular information from the fossil record – that’s protein sequenced in 2016 from 3.8-million-year-old ostrich eggshells from Tanzania. In second place is a protein sequence from a 1.77-million-year-old rhinoceros tooth from Georgia, which was analyzed in 2019. However, while protein is hardier and can survive in extremely old fossils from places without permafrost, it isn’t as useful as DNA for researchers who want to study an organism’s ancestry.
That’s just one of the reasons why the new mammoth DNA study is so important – it contains genetic information which hasn’t been available in the older protein samples.
A second reason why the study is making headlines is that it has beaten ancient DNA from a genome from a 560,000 to 780,000-year-old horse leg bone found in the Yukon Territory of Canada for the oldest ancient DNA sequence. Putting the age of the mammoth samples into context, Dalén said:
“This DNA is incredibly old. The samples are a thousand times older than Viking remains, and even pre-date the existence of humans and Neanderthals.”
The First Example of Hybrid Speciation in Ancient DNA
The new study has also amplified the ability for researchers to track the evolutionary process of speciation – the formation of new and distinct species. A Nature press release states that this process generally occurs “over time periods that are thought to be beyond the limits of DNA research.”
A tusk from a woolly mammoth discovered in a creek bed on Wrangel Island in 2017. (Credit: Love Dalén)
Nonetheless, the scientists’ study of the mammoth DNA suggests that there was not one, but two different lineages of mammoth alive during the Early Pleistocene in the region of what is now eastern Siberia. Adycha and Chukochya are believed to be members of a species that spawned the woolly mammoth, but Krestovka appears to come from an unknown, and possibly entirely new, mammoth lineage. Tom van der Valk, the study’s lead author and a bioinformatician at the University of Uppsala in Sweden, explains the researchers’ shock at this discovery:
“This came as a complete surprise to us. All previous studies have indicated that there was only one species of mammoth in Siberia at that point in time, called the steppe mammoth. But our DNA analyses now show that there were two different genetic lineages, which we here refer to as the Adycha mammoth and the Krestovka mammoth. We can’t say for sure yet, but we think these may represent two different species.”
In their study, the researchers suggest that the Krestovka genome may have diverged from the other mammoths between 2.66 to 1.78 million years ago. They also believe that this mammoth lineage “was ancestral to the first mammoths to colonize North America.” It appears that the North American Columbian mammoths ( Mammuthus columbi ) can trace half of their ancestry to wooly mammoths and half to the previously unrecognized Krestovka mammoth lineage.
The Nature news report states that this means the new study has also provided the first evidence for ‘hybrid speciation’ – a new species forming through mixing – found in ancient DNA. Study co-lead author Patrícia Pečnerová, an evolutionary biologist at the Swedish Museum of Natural History, says that the team believes “that the Columbian mammoth, one of the most iconic Ice Age species of North America, evolved through a hybridisation that took place approximately 420 thousand years ago.”
How Far Back Can Researchers Go?
Finally, the ancient mammoth DNA study has inspired Dalén to analyze more permafrost animal samples that date back more than a million years. Next on his list? Musk oxen, moose, and lemmings. But the professor of evolutionary genetics knows that there is an age limit he won’t be able to cross when analyzing the ancient DNA – 2.6 million years – “That’s the limit of the permafrost. Before that, it was too warm,” he says.
Woolly mammoth tusk emerging from permafrost on central Wrangel Island, located in northeastern Siberia. (Credit: Love Dalén)
Top Image: The illustration represents a reconstruction of the steppe mammoths that preceded the woolly mammoth, based on the genetic knowledge we now have from the Adycha mammoth. Source: Beth Zaiken/Centre for Palaeogenetics
