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World’s oldest DNA sequenced from million-year-old mammoths – Al Jazeera English

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Teeth from mammoths buried in the Siberian permafrost for more than a million years have yielded the oldest DNA ever sequenced, according to a study published on Wednesday, shining a genetic spotlight into the deep past.

Researchers said the three specimens, one roughly 800,000 years old and two more than a million years old, provide important insights into the giant Ice Age mammals, including the ancient heritage of the woolly mammoth.

The genomes far exceed the oldest previously sequenced DNA – a horse dating to between 780,000 and 560,000 years ago.

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“This DNA is incredibly old. The samples are a thousand times older than Viking remains, and even predate the existence of humans and Neanderthals,” said Love Dalen, a professor of evolutionary genetics at the Centre for Palaeogenetics in Stockholm and the senior author of the study published in the journal, Nature.

The mammoths were originally discovered in the 1970s in Siberia and held at the Russian Academy of Sciences in Moscow.

Researchers first dated the specimens geologically, with comparisons to other species, like small rodents, known to be unique to particular time periods and found in the same sedimentary layers.

This suggested that two of the mammals were ancient steppe mammoths more than a million years old.

The youngest of the trio is one of the earliest woolly mammoths yet found.

DNA jigsaw

Researchers also extracted genetic data from tiny samples of powder from each mammoth tooth, “essentially like a pinch of salt you would put on your dinner plate,” Dalen told a press briefing.

A woolly mammoth tusk emerges from the permafrost on central Wrangel Island in northeastern Siberia. Analysis of teeth from the animals has yielded the oldest DNA ever sequenced [Love Dalén via AFP]

While it had degraded into very small fragments, scientists were able to sequence tens of millions of chemical base pairs, which make up the strands of DNA and conduct age estimates from the genetic information.

This suggested that the oldest mammoth, named Krestovka, is even older at approximately 1.65 million years old, while the second, Adycha, is about 1.34 million years old and the youngest Chukochya is 870,000 years old.

Dalen said the discrepancy for the oldest mammoth could be an underestimation in the DNA dating process, meaning the creature was likely around 1.2 million years old, as suggested by the geological evidence.

But he said it was possible the specimen was indeed older and had thawed out of the permafrost at one point and then become wedged in a younger layer of sediment.

The DNA fragments were like a puzzle with millions of tiny pieces, “way, way, way smaller than you would get from modern, high-quality DNA”, said lead author Tom van der Valk, of the Science for Life Laboratory, Uppsala University.

Using a genome from an African elephant, a modern relative of the mammoth, as a blueprint for their algorithm, researchers were able to reconstruct parts of the mammoth genomes.

The study found that the older Krestovka mammoth represents a previously unrecognised genetic lineage, which researchers estimated diverged from other mammoths around two million years ago and was ancestral to those that colonised North America.

The study also traced the lineage from the million-year-old Adycha steppe mammoth to Chukochya and other more recent woolly mammoths.

It found gene variants associated with life in the Arctic, like hairiness, thermoregulation, fat deposits and cold tolerance in the older specimen, suggesting mammoths were already hairy long before the woolly mammoth emerged.

Ice Age giants

Siberia has alternated between dry and cold Ice Age conditions and warm, wet periods.

Now climate change is melting the permafrost and revealing more specimens, Dalen said, although increased rainfall could mean remains are washed away.

He said new technologies mean it may be possible to sequence even older DNA from remains found in the permafrost, which dates back 2.6 million years.

Researchers are keen to look at creatures such as the ancestors of moose, muskox, wolves and lemmings, to shine a light on the evolution of modern species.

“Genomics has been pushed into deep time by the giants of the Ice Age,” said Alfred Roca, a professor in the Department of Animal Sciences at the University of Illinois, in a comment piece published in Nature.

“The wee mammals that surrounded them might soon also have their day.”

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Marine plankton could act as alert in mass extinction event: UVic researcher – Langley Advance Times

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A University of Victoria micropaleontologist found that marine plankton may act as an early alert system before a mass extinction occurs.

With help from collaborators at the University of Bristol and Harvard, Andy Fraass’ newest paper in the Nature journal shows that after an analysis of fossil records showed that plankton community structures change before a mass extinction event.

“One of the major findings of the paper was how communities respond to climate events in the past depends on the previous climate,” Fraass said in a news release. “That means that we need to spend a lot more effort understanding recent communities, prior to industrialization. We need to work out what community structure looked like before human-caused climate change, and what has happened since, to do a better job at predicting what will happen in the future.”

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According to the release, the fossil record is the most complete and extensive archive of biological changes available to science and by applying advanced computational analyses to the archive, researchers were able to detail the global community structure of the oceans dating back millions of years.

A key finding of the study was that during the “early eocene climatic optimum,” a geological era with sustained high global temperatures equivalent to today’s worst case global warming scenarios, marine plankton communities moved to higher latitudes and only the most specialized plankton remained near the equator, suggesting that the tropical temperatures prevented higher amounts of biodiversity.

“Considering that three billion people live in the tropics, the lack of biodiversity at higher temperatures is not great news,” paper co-leader Adam Woodhouse said in the release.

Next, the team plans to apply similar research methods to other marine plankton groups.

Read More: Global study, UVic researcher analyze how mammals responded during pandemic

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Scientists Say They Have Found New Evidence Of An Unknown Planet… – 2oceansvibe News

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In the new work, scientists looked at a set of trans-Neptunian objects, or TNOs, which is the technical term for those objects that sit out at the edge of the solar system, beyond Neptune

The new work looked at those objects that have their movement made unstable because they interact with the orbit of Neptune. That instability meant they were harder to understand, so typically astronomers looking at a possible Planet Nine have avoided using them in their analysis.

Researchers instead looked towards those objects and tried to understand their movements. And, Dr Bogytin claimed, the best explanation is that they result from another, undiscovered planet.

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The team carried out a host of simulations to understand how those objects’ orbits were affected by a variety of things, including the giant planets around them such as Neptune, the “Galactic tide” that comes from the Milky Way, and passing stars.

The best explanation was from the model that included Planet 9, however, Dr Bogytin said. They noted that there were other explanations for the behaviour of those objects – including the suggestion that other planets once influenced their orbit, but have since been removed – but claim that the theory of Planet 9 remains the best explanation.

A better understanding of the existence or not of Planet 9 will come when the Vera C Rubin Observatory is turned on, the authors note. The observatory is currently being built in Chile, and when it is turned on it will be able to scan the sky to understand the behaviour of those distant objects.

Planet Nine is theorised to have a mass about 10 times that of Earth and orbit about 20 times farther from the Sun on average than Neptune. It may take between 10,000 and 20,000 Earth years to make one full orbit around the Sun.

You may be tempted to ask how an entire planet could ‘hide’ in our solar system when we have zooming capabilities such as the new iPhone 15 has, but consider this: If Earth was the size of a marble, the edge of our solar system would be 11 kilometres away. That’s a lot of space to hide a planet.

[source:independent]

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Dragonfly: NASA Just Confirmed The Most Exciting Space Mission Of Your Lifetime – Forbes

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NASA has confirmed that its exciting Dragonfly mission, which will fly a drone-like craft around Saturn’s largest moon, Titan, will cost $3.35 billion and launch in July 2028.

Titan is the only other world in the solar system other than Earth that has weather and liquid on the surface. It has an atmosphere, rain, lakes, oceans, shorelines, valleys, mountain ridges, mesas and dunes—and possibly the building blocks of life itself. It’s been described as both a utopia and as deranged because of its weird chemistry.

Set to reach Titan in 2034, the Dragonfly mission will last for two years once its lander arrives on the surface. During the mission, a rotorcraft will fly to a new location every Titan day (16 Earth days) to take samples of the giant moon’s prebiotic chemistry. Here’s what else it will do:

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  • Search for chemical biosignatures, past or present, from water-based life to that which might use liquid hydrocarbons.
  • Investigate the moon’s active methane cycle.
  • Explore the prebiotic chemistry in the atmosphere and on the surface.

Spectacular Mission

“Dragonfly is a spectacular science mission with broad community interest, and we are excited to take the next steps on this mission,” said Nicky Fox, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington. “Exploring Titan will push the boundaries of what we can do with rotorcraft outside of Earth.”

It comes in the wake of the Mars Helicopter, nicknamed Ingenuity, which flew 72 times between April 2021 and its final flight in January 2023 despite only being expected to make up to five experimental test flights over 30 days. It just made its final downlink of data this week.

Dense Atmosphere

However, Titan is a completely different environment to Mars. Titan has a dense atmosphere on Titan, which will make buoyancy simple. Gravity on Titan is just 14% of the Earth’s. It sees just 1% of the sunlight received by Earth.

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The atmosphere is 98% nitrogen and 2% methane. Its seas and lakes are not water but liquid ethane and methane. The latter is gas in Titan’s atmosphere, but on its surface, it exists as a liquid in rain, snow, lakes, and ice on its surface.

COVID-Affected

Dragonfly was a victim of the pandemic. Slated to cost $1 billion when it was selected in 2019, it was meant to launch in 2026 and arrive in 2034 after an eight-year cruise phase. However, after delays due to COVID, NASA decided to compensate for the inevitable delayed launch by funding a heavy-lift launch vehicle to massively shorten the mission’s cruise phase.

The end result is that Dragonfly will take off two years later but arrive on schedule.

Previous Visit

Dragonfly won’t be the first time a robotic probe has visited Titan. As part of NASA’s landmark Cassini mission to Saturn between 2004 and 2017, a small probe called Huygens was despatched into Titan’s clouds on January 14, 2005. The resulting timelapse movie of its 2.5 hours descent—which heralded humanity’s first-ever (and only) views of Titan’s surface—is a must-see for space fans. It landed in an area of rounded blocks of ice, but on the way down, it saw ancient dry shorelines reminiscent of Earth as well as rivers of methane.

The announcement by NASA makes July 2028 a month worth circling for space fans, with a long-duration total solar eclipse set for July 22, 2028, in Australia and New Zealand.

Wishing you clear skies and wide eyes.

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