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Russia: Passengers ‘get out and push’ frozen plane

Homeward bound: Frozen brake pads were no match for these passengers

Passengers due to take a flight in Siberia had to get out and push the aircraft after its brake pads froze solid, it’s reported.

The plane was trying to take off from the Russian town of Igarka, but was unable to move after the temperature fell to -52C.

Source: BBCNews Read more

Neanderthal Sex

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Ancient human bone helps date our first sex with Neanderthals

Oldest genome sequence of a modern human suggests Homo sapiens first bred with Neanderthals 50,000-60,000 years ago

Neanderthal DNA specialist Svante Pääbo examines the anatomically modern human femur, found near Ust’-Ishim in western Siberia. Photograph: Bence Viola/MPI EVA

An ancient leg bone found by chance on the bank of a Siberian river has helped scientists work out when early humans interbred with our extinct cousins, the Neanderthals.

A local ivory carver spotted the bone sticking out of sediments while fossil hunting in 2008 along the Irtysh river near the settlement of Ust’-Ishim in western Siberia. The bone was later identified as a human femur, but researchers have learned little else about the remains until now.

The importance of the find became clear when a team led by Svante Pääbo and Janet Kelso at the Max Planck Institute for Evolutionary Anthropology in Leipzig ran a series of tests on the fragile material.

Radiocarbon dating of pieces of the leg bone put the remains at around 45,000 years old. The team went on to extract DNA from the bone, which allowed them to reconstruct the oldest modern human genome ever.

The genetic material showed that the thigh bone belonged to a man who carried about 2% Neanderthal DNA, a similar amount to people from Europe and Asia today. The presence of Neanderthal DNA meant that interbreeding between them and modern humans must have taken place at least 45,000 years ago.

But amid the DNA were more clues to when humans and Neanderthals reproduced. Strands of Neanderthal DNA found in modern humans can act like a biological clock, because they are fragmented more and more with each generation since interbreeding happened. The strands of Neanderthal DNA in the Siberian man were on average three times longer than those seen in people alive today. Working backwards, the scientists calculate that Neanderthals contributed to the man’s genetic ancestry somewhere between 7,000 and 13,000 years before he lived.

The findings, published in the journal Nature, suggest that humans and Neanderthals had reproductive sex around 50,000 to 60,000 years ago, though other couplings might well have happened later. Until now, estimates for interbreeding have varied enormously, ranging from 37,000 to 86,000 years ago.

“What we think may be the case is that the ancestors of the Ust’-Ishim man met and interbred with Neanderthals during the initial early admixture event that is shared by all non-Africans at between 50,000 and 60,000 years ago, and perhaps somewhere in the middle East,” Kelso told the Guardian.

But a small number of fragments of Neanderthal DNA in the man’s genome were longer than expected given how many generations had passed. Those might be evidence of his ancestors breeding with Neanderthals closer to the time he was born.

“Everyone outside Africa has about same amount of Neanderthal DNA. It seems to be something early on where one really mixed with Neanderthals in a serious way,” said Pääbo. “Since that happened I wouldn’t be surprised if, now and again, one did it here and there later on too.”

Prior to the latest study, the oldest modern human genome came from the 24,000-year-old remains of a boy buried at Mal’ta near Lake Baikal in easterbn Siberia.

Chris Stringer, head of human origins at the Natural History Museum in London, said the ancient DNA from the Siberian man sheds fresh light on the story of early human migrations out of Africa. In the 1920s and 30s, researchers found 100,000-year-old skeletons of modern humans in caves in Israel. The remains may have belonged to a group of humans that left Africa and ultimately went on to colonise southern Asia, Australia and New Guinea. But an alternative explanation is that they were from a migration that failed to go much further. According to that view, the more successful dispersal of humans out of Africa happened much later, around 60,000 years ago.

The latest findings suggest that the ancestors of modern Australians, who carry a similar amount of Neanderthal DNA to Europeans and Asians, are unlikely to have picked up their own Neanderthal DNA before 60,000 years ago. “The ancestors of Australasians must have been part of a late, rather than early, dispersal through Neanderthal territory,” Stringer said.

“While it is still possible that modern humans did traverse southern Asia before 60,000 years ago, those groups could not have made a significant contribution to the surviving modern populations outside of Africa, which contain evidence of interbreeding with Neanderthals,” he added.

Source: TheGuardian

Europeans drawn from three ancient ‘tribes’

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The modern European gene pool was formed when three ancient populations mixed within the last 7,000 years, Nature journal reports.

Blue-eyed, swarthy hunters mingled with brown-eyed, pale skinned farmers as the latter swept into Europe from the Near East.

But another, mysterious population with Siberian affinities also contributed to the genetic landscape of the continent.

The findings are based on analysis of genomes from nine ancient Europeans.

Agriculture originated in the Near East – in modern Syria, Iraq and Israel – before expanding into Europe around 7,500 years ago.

Multiple lines of evidence suggested this new way of life was spread by a wave of migrants, who interbred with the indigenous European hunter-gatherers they encountered on the way.

But assumptions about European origins were based largely on the genetic patterns of living people. The science of analysing genomic DNA from ancient bones has put some of the prevailing theories to the test, throwing up a few surprises.

Genomic DNA contains the biochemical instructions for building a human, and resides within the nuclei of our cells.

In the new paper, Prof David Reich from the Harvard Medical School and colleagues studied the genomes of seven hunter-gatherers from Scandinavia, one hunter whose remains were found in a cave in Luxembourg and an early farmer from Stuttgart, Germany.

The hunters arrived in Europe thousands of years before the advent of agriculture, hunkered down in southern refuges during the Ice Age and then expanded during a period called the Mesolithic, after the ice sheets had retreated from central and northern Europe.

Their genetic profile is not a good match for any modern group of people, suggesting they were caught up in the farming wave of advance.

However, their genes live on in modern Europeans, to a greater extent in the north-east than in the south.

The early farmer genome showed a completely different pattern, however. Her genetic profile was a good match for modern people in Sardinia, and was rather different from the indigenous hunters.

But, puzzlingly, while the early farmers share genetic similarities with Near Eastern people at a global level, they are significantly different in other ways. Prof Reich suggests that more recent migrations in the farmers’ “homeland” may have diluted their genetic signal in that region today.

Prof Reich explained: “The only way we’ll be able to prove this is by getting ancient DNA samples along the potential trail from the Near East to Europe… and seeing if they genetically match these predictions or if they’re different.

“Maybe they’re different – that would be extremely interesting.”

Source: BBCNews Read and see more

Do we Really Need Mammoths?

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Woolly mammoth remains may contain living cells

Hair, soft tissues and bone marrow found on Siberian expedition, raising hopes that extinct creature could be cloned

Frozen fragments of a woolly mammoth have been found by an international expedition of scientists in Siberia, Russia. Photograph: Bettmann/Corbis 

A Russian university says scientists have discovered frozen woolly mammoth fragments that may contain living cells deep in Siberia, bringing closer the possibility of cloning the extinct animal.

The North-Eastern Federal University said in a statement on Tuesday that an international team had discovered mammoth hair, soft tissues and bone marrow at a depth of 328ft (100m) during a summer expedition.

Expedition chief Semyon Grigoryev said a group of Korean scientists with the team had set a goal of finding living cells in the hope of cloning a mammoth. Scientists have previously found bodies and fragments, but not living cells.

Grigoryev told online newspaper Vzglyad it would take months of lab research to determine whether they have indeed found the cells.

Woolly mammoths are thought to have died out 10,000 years ago.

Deadly railway to nowhere

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In the Russian Arctic lies buried an unfinished railway built by prisoners of Stalin’s gulags. For decades no-one talked about it. But one woman is now telling the story of the thousands who suffered there – and there is talk of bringing back to life the abandoned railway itself.

The remains of Joseph Stalin’s railway

There are so many stories in this world that remain untold, this is one of them. Freezing temperatures, baby mammoths and hardship, but beyond all, the human spirit.

Read the BBC News story and see if you are not moved.

 

Ancient plants back to life after 30,000 frozen years

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Scientists in Russia have grown plants from fruit stored away in permafrost by squirrels over 30,000 years ago.

The fruit was found in the banks of the Kolyma River in Siberia, a top site for people looking for mammoth bones.

The Institute of Cell Biophysics team raised plants of Silene stenophylla – of the campion family – from the fruit.

Writing in Proceedings of the National Academy of Sciences (PNAS), they note this is the oldest plant material by far to have been brought to life.

Prior to this, the record lay with date palm seeds stored for 2,000 years at Masada in Israel….

Sugar sweet

Back in the lab, near Moscow, the team’s attempts to germinate mature seeds failed.

Silene stenophylla Eventually they found success using elements of the fruit itself, which they refer to as “placental tissue” and propagated in laboratory dishes.

“This is by far the most extraordinary example of extreme longevity for material from higher plants,” commented Robin Probert, head of conservation and technology at the UK’s Millennium Seed Bank.

“I’m not surprised that it’s been possible to find living material as old as this, and this is exactly where we would go looking, in permafrost and these fossilised rodent burrows with their caches of seeds.

“But it is a surprise to me that they’re finding viable material from this placental tissue rather than mature seeds.”

The Russian team’s theory is that the tissue cells are full of sucrose that would have formed food for the growing plants.

Sugars are preservatives; they are even being researched as a way of keeping vaccines fresh in the hot climates of Africa without the need for refrigeration.

So it may be that the sugar-rich cells were able to survive in a potentially viable state for so long.

Silene stenophylla still grows on the Siberian tundra; and when the researchers compared modern-day plants against their resurrected cousins, they found subtle differences in the shape of petals and the sex of flowers, for reasons that are not evident.

Source: BBC News Read more

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