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Woolly Mammoth - Mammuthus primigenius
#31
North American Mammoths Actually Evolved in Eurasia

by Laura Geggel, Staff Writer | November 12, 2015 05:50pm ET

[Image: primative-mammoth.jpg]
The European mammoth species, Mammuthus meridionalis, likely never made it to North America, a new study finds.
Credit: Copyright A.Vlachos, G.Lyras

The famous Columbian mammoth — an 11-ton creature known for traversing North America during the last ice age — might actually be the same species as the Eurasian steppe mammoth, a new study finds.

The discovery suggests that the first mammoth to enter North America was the Eurasian steppe mammoth, and not its ancestor, a European creature called Mammuthus meridionalis. The two species differed greatly — the steppe mammoth had many more adaptations to living in cold weather.

The finding helps to rewrite the story of the evolution of the mammoth in North America, said study co-researcher Adrian Lister, a research leader of paleontology at the Natural History Museum in London. 

But to understand the latest development, it's important to explain the history of mammoth evolution, Lister said. Mammoths first emerged in Africa about 5 million years ago and moved into Europe about 3 million years ago, before spreading across Asia. When the mammoths first reached Eurasia, they were "still a forest-living, warm-climate kind of elephant species," Lister told Live Science. "And then, through about 2 [million] or 3 million years of evolution, they turned into the familiar woolly mammoth of the ice age."

[Image: columbian-mammoth.jpg]
The Columbian mammoth (Mammuthus columbi) lived in North America during the Pleistocene.
Credit: Copyright Michael Long, Trustees of NHM, London

However, earlier research suggests that one of these warm-climate mammoths, the European Mammuthus meridionalis, made the long trek across the Bering Strait land bridge about 1.5 million years ago. It was thought that once it reached North America, the behemoth gave rise to the famous Columbian mammoth (Mammuthus columbi), which had a stomping ground that ranged from Canada to central Mexico, Lister said.

But there's only shaky evidence that this European mammoth lived in North America, he said. Researchers base much of their findings on mammoth teeth, as the rest of the skeleton isn't always preserved or discovered. Whenever an ambiguous — or less developed — mammoth tooth is found in North America, scientists typically assign it to the European mammoth species, Lister said.

But these teeth may simply look less developed because they are worn down from chewing, and were likely more complex in the mammoth's youth, Lister said.

"When you look at these worn teeth, they look more primitive than they really are," he said. Most of the more complex teeth are attributed to the Columbian mammoth, but it's possible that these worn teeth belong to the Columbian, too, he said.

Fossil evidence

The fossil record seems to support this idea. There are no known fossils belonging to the European mammoth in northeast Siberia or Alaska, "suggesting that this temperate-adapted species never dispersed as far north as the Beringian transit route," the researchers wrote in the study.

But researchers found the remains of the steppe mammoth (Mammuthus trogontherii) in northeast China dating to 1.7 million years ago, and in northeast Siberia dating to 1.2 million to 0.8 million years ago, Lister said. This makes the steppe mammoth a good candidate for the 1.5-million-year-old crossing into North America, he added.

Moreover, after a recent trip in which he analyzed hundreds of mammoth specimens (mostly teeth) in museums across the United States, Lister came to the realization that the steppe and the Columbian mammoth are likely the same species. 

"When we compared these steppe mammoths from Asia with the American Columbian mammoth, we found that they were virtually identical," Lister said. "The new idea is that this advanced mammoth actually evolved in Siberia and just moved over to North America, where it's called the Columbian mammoth, but it's really more of the same thing."

[Image: Steppe-mammoth-tusks.jpg]
The tusks of a steppe mammoth (Mammuthus trogontherii), which is likely the same species as the Columbian mammoth, experts say.
Credit: Copyright Trustees of NHM, London

He joked that because the Columbian mammoth was named in 1857, almost 30 years before the steppe mammoth was named in 1885, technically all of these mammoths should adopt the name Mammuthus columbi.

This is a very "embarrassing name" for European scientists, who are used to calling it Mammuthus trogontherii, Lister said, laughing. Only time will tell how long that change will take, he said.

The researchers also reported that the Eurasian woolly mammoth (Mammuthus primigenius) later followed the steppe/Columbian mammoth into North America, but lived farther north, in the colder areas of southern Canada and the northern continental United States. However, the Eurasian woolly mammoth's range overlapped with its relatives, likely leading to interbreeding that birthed hybrid species, including Mammuthus jeffersonii, Lister said.

The study presents a compelling case that the steppe/Columbian mammoth was the first to reach North America, said Daniel Fisher, a University of Michigan paleontologist who was not involved in the new study.

However, it's impossible to say whether the worn-down teeth belong to an earlier or more advanced species, simply because there are few identifying characteristics on them, Fisher said. "[But] I'm happy enough to take this as the best statement, the best call of what is probably going on," he said.

Lister co-authored the study with Andrei Sher, a paleontologist with the Severtsov Institute of Ecology and Evolution in Moscow, who died in 2007 before the study's completion. The findings were published online today (Nov. 12) in the journal Science.

http://www.livescience.com/52785-north-american-mammoths.html




Evolution and dispersal of mammoths across the Northern Hemisphere

A. M. Lister, A. V. Sher
Science 13 November 2015: Vol. 350 no. 6262 pp. 805-809 
DOI: 10.1126/science.aac5660


ABSTRACT
Mammoths provide a detailed example of species origins and dispersal, but understanding has been impeded by taxonomic confusion, especially in North America. The Columbian mammoth Mammuthus columbi was thought to have evolved in North America from a more primitive Eurasian immigrant. The earliest American mammoths (1.5 million years ago), however, resemble the advanced Eurasian M. trogontherii that crossed the Bering land bridge around that time, giving rise directly to M. columbi. Woolly mammoth M. primigenius later evolved in Beringia and spread into Europe and North America, leading to a diversity of morphologies as it encountered endemic M. trogontherii and M. columbi, respectively. In North America, this included intermediates (“M. jeffersonii”), suggesting introgression of M. primigenius with M. columbi. The lineage illustrates the dynamic interplay of local adaptation, dispersal, and gene flow in the evolution of a widely distributed species complex.

http://www.sciencemag.org/content/350/6262/805 
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#32
Mammoth kill linked to earliest Arctic settlers

By Jonathan Amos
BBC Science Correspondent
15 January 2016

[Image: _87721877_thinkstockphotos-529747969.jpg]
Artist's impression: Being able to exploit mammoths gave humans the means to colonise the Arctic

A well preserved mammoth carcass pulled from frozen sediments in the far north of Russia proves humans were present in the Arctic some 45,000 years ago.
This is 10,000 years earlier than previous evidence had indicated.
The extinct animal's bones display distinctive cut marks that can only have been produced by stone and ivory-tipped hunting and butchery tools.
Being able to exploit mammoths would have been key to these early settlers' spread and survival in the Arctic.
Not only would the great beasts have represented a high-energy food source, but their tusks and bones would have been a source of practical materials in a landscape where there are few suitable rocks from which to make spear tips, and other critical technologies.
"Not all areas - and the location of the mammoth find is among them - provide good lithic raw material. This is very typical for most of northern West Siberia," explained Vladimir Pitulko, who is part of the team that reports the discovery in this week's Science magazine.
He told the BBC that everything about the way these Arctic colonisers took down the mammoth demonstrates them to have been "very skilled and organised hunters and tool makers".

[Image: _87721776_pitulko1hrb.jpg]
The animal was probably around 15 years old at the time of death
copyright PITULKO ET AL

The carcass was uncovered from a steep bank on the eastern shore of Siberia's remote Yenisei Bay, very close to the Sopochnaya Karga (SK) meteorological station. The latitude is 72 degrees North. By way of comparison, the previous firmly dated evidence for human occupation this far north comes from 35,000 years ago.
The mammoth has various injuries to its head and ribs, but perhaps the most intriguing is the puncture mark in a cheek bone. Dr Pitulko and colleagues say it was produced by a sharp, robust implement, and from its geometry was very likely delivered when the animal was on the ground.
They write in their Science paper: "This injury itself is probably the result of a missed blow, targeting the base of the trunk.
"This specific hunting method is still practised in Africa by elephant hunters, who target the base of the trunk to cut major arteries and cause mortal bleeding. This blow becomes necessary after the animal has been sufficiently injured, and the SK mammoth displays numerous injuries in the thoracic (chest) area."
The team discusses the mammoth find in the context of other archaeological discoveries from across the Siberian Arctic. The researchers build a picture of human settlers getting themselves close enough to the far northeast of Russia that they could have made an early bid to cross into North America before the last ice age became so severe that the way would have been blocked. This would have been prior to 30,000 years ago.
Currently, the evidence in northwest America does not support this, but Dr Pitulko said he and other scientists would continue to investigate the idea.
"These finds change our mind on possible options and this is going to give a new stimulus for further research," he told BBC News.
"These finds do not give an immediate answer, but allow thinking about the possibilities."
Dr Pitulko is affiliated to the Institute for the History of Material Culture, at the Russian Academy of Sciences, in St Petersburg.

http://www.bbc.com/news/science-environment-35320938




Journal Reference
Vladimir V. Pitulko, Alexei N. Tikhonov, Elena Y. Pavlova, Pavel A. Nikolskiy, Konstantin E. Kuper, Roman N. Polozov. Early human presence in the Arctic: Evidence from 45,000-year-old mammoth remains. Science 15 Jan 2016: Vol. 351, Issue 6270, pp. 260-263 DOI: 10.1126/science.aad0554

Abstract
Archaeological evidence for human dispersal through northern Eurasia before 40,000 years ago is rare. In west Siberia, the northernmost find of that age is located at 57°N. Elsewhere, the earliest presence of humans in the Arctic is commonly thought to be circa 35,000 to 30,000 years before the present. A mammoth kill site in the central Siberian Arctic, dated to 45,000 years before the present, expands the populated area to almost 72°N. The advancement of mammoth hunting probably allowed people to survive and spread widely across northernmost Arctic Siberia.

http://science.sciencemag.org/content/351/6270/260
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#33
'Lack of water' killed last woolly mammoths

By Rebecca Morelle
Science Correspondent, BBC News

[Image: _90605265_c0205129-woolly_mammoth_artwork-spl.jpg]
The mammoths on St Paul Island outlived their mainland cousins by thousands of years
SCIENCE PHOTO LIBRARY

One of the last known groups of woolly mammoths died out because of a lack of drinking water, scientists believe.
The Ice Age beasts were living on a remote island off the coast of Alaska, and scientists have dated their demise to about 5,600 years ago.
They believe that a warming climate caused lakes to become shallower, leaving the animals unable to quench their thirst.
Most of world's woolly mammoths had died out by about 10,500 years ago.
Scientists believe that human hunting and environmental changes played a role in their extinction.
But the group living on St Paul Island, which is located in the Bering Sea, managed to cling on for another 5,000 years.
This study in the Proceedings of the National Academy of Sciences suggests that these animals faced a different threat from their mainland cousins.
As the Earth warmed up after the Ice Age, sea levels rose, causing the mammoths' island home to shrink in size.
This meant that some lakes were lost to the ocean, and as salt water flowed into the remaining reservoirs, freshwater diminished further.
The fur-covered giants were forced to share the ever-scarcer watering holes. But their over-use also caused a major problem.

Congregating mammoths

Lead author Prof Russell Graham, from Pennsylvania State University, said: "As the other lakes dried up, the animals congregated around the water holes.
"They were milling around, which would destroy the vegetation - we see this with modern elephants.
"And this allows for the erosion of sediments to go into the lake, which is creating less and less fresh water, making the lake less shallow.
"The mammoths were contributing to their own demise."
He said that if there was not enough rain or melting snow to top the lakes up, the animals may have died very quickly.
"We do know modern elephants require between 70 and 200 litres of water daily," Prof Graham said.
"We assume mammoths did the same thing. It wouldn't have taken long if the water hole had dried up. If it had only dried up for a month, it could have been fatal."
The researchers say climate change happening today could have a similar impact on small islands, with a threat to freshwater putting both animals and humans at risk.

'Best understood extinction'

Commenting on the study, Love Dalen, professor in evolutionary genetics at the Swedish Museum of Natural History, said: "With this paper, the St Paul Island mammoth population likely represents the most well-described and best understood prehistoric extinction events.
"In a broader perspective, this study highlights that small populations are very sensitive to changes in the environment."
The very last surviving mammoths lived on Wrangel Island, in the Arctic Ocean. It is thought they died out 4,000 years ago.

http://www.bbc.com/news/science-environment-36945909




Journal Reference:
Russell W Graham et. al. Timing and causes of mid-Holocene mammoth extinction on St. Paul Island, Alaska. PNAS, August 1, 2016, doi: 10.1073/pnas.1604903113 

Abstract
Relict woolly mammoth (Mammuthus primigenius) populations survived on several small Beringian islands for thousands of years after mainland populations went extinct. Here we present multiproxy paleoenvironmental records to investigate the timing, causes, and consequences of mammoth disappearance from St. Paul Island, Alaska. Five independent indicators of extinction show that mammoths survived on St. Paul until 5,600 ± 100 y ago. Vegetation composition remained stable during the extinction window, and there is no evidence of human presence on the island before 1787 CE, suggesting that these factors were not extinction drivers. Instead, the extinction coincided with declining freshwater resources and drier climates between 7,850 and 5,600 y ago, as inferred from sedimentary magnetic susceptibility, oxygen isotopes, and diatom and cladoceran assemblages in a sediment core from a freshwater lake on the island, and stable nitrogen isotopes from mammoth remains. Contrary to other extinction models for the St. Paul mammoth population, this evidence indicates that this mammoth population died out because of the synergistic effects of shrinking island area and freshwater scarcity caused by rising sea levels and regional climate change. Degradation of water quality by intensified mammoth activity around the lake likely exacerbated the situation. The St. Paul mammoth demise is now one of the best-dated prehistoric extinctions, highlighting freshwater limitation as an overlooked extinction driver and underscoring the vulnerability of small island populations to environmental change, even in the absence of human influence.


Attached to this post:[Image: attach.png] Timing_and_causes_of_mid_Holocene_mammoth_extinction_on_St._Paul_Island__Alaska.pdf (3.21 MB)
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#34
Mammuthus Wrote:Gestation period in Mammoths
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Finding the gestation period of Mammoth requires looking at the gestation period of Elephants. African Elephants tend to have a gestation period of 650 days (21 months) and it isn't any different in captive African Elephants, its does not differ much in Asian Elephants as their gestation period is roughly 660 days. Giving the gestation periods of modern-day Elephants you could imagine Mammoths gestation periods shouldn't be any different, but for now there is no evidence to suggest its similar. 

The season of birth will depend on the gestation length and season of conception, conception tends to occur year-round in African Elephants but there can be seasonal peaks (like the rainy season) when productivity is much higher. Majority of conceptions carried to term happened following seasonal peaks in prime productivity and given the 650 day gestation, births happen closer to the onset of seasonal increases in primary production. Mammoths would of been likely similar but potentially more extreme seasonal abnormality in nutrients availability and could of restrained the birth of calves to correspond with the start of the growing season. If we consider that Mammoths alike Elephants had condition dependent estrus, the greatest time for breeding could of been from August to October like that of Muskoxen and Caribou other Tundra animals. If you then assume the gestation period was similar to that of extant Elephants and that births would of been timed just before the growing season, you could predict that the gestation period would of been roughly 20 months.

Using teeth to find gestations lengths in Mammoths

Tooth eruption and wear is usually used to predict the age of an Elephant and this system can also be used to predict the age of a Mammoth. Unfortunately it has not been used on a Mammoth tooth due to there being differences in wear rates for Mammoths when compared to African Elephants. Unfortunately the initiation of tooth mineralization hasn't been studied well in African Elephant foetuses. The average length of an African Elephant foetus is roughly 21cm and using evidence you could estimate  the metal age to be 192 days. A mandible from a 9.5cm African Elephant foetus that corresponded to a metal age of around 140 days, but the amount of mineralization sadly wasn't mentioned. Mineralised-tissue occurs in the deciduous tusk. The crown formation in the deciduous tusk is finished after 16 months.

The dentin grows by accretion and periodic growth appear at distinct temporal scales. In Mammoths however, first oder growth increments occur each year in periodicity. Second-order increments have a period of roughly 7 days, and third-order increments happen daily. Applying these growth increments you could then predict the period of time over which a tooth would be formed.

Teeth do not begin to mineralize at conception, so the period of prenatal dentin accretion in a Mammoth tooth does not directly give us the gestation period of mammoths. By itself, the period of prenatal dentin accretion gives an underestimate of gestation length. In combination with comparative data from elephants, it permits estimation of relative gestation length. For example, thedP2s in African elephants have a prenatal mineralization period of about 15 months 17 months (for initiation between 140 and 192 days of gestation). If we observe a similar prenatal mineralization period in Mammoths, we could infer that their gestation lengths were probably similar.

Mammuthus Wrote:Mammoth herd structures and migrations paths, and more
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Many pleistocene fossil sights contain the remains of many Mammoths, some of the sights represent the mass death of entire herds. These assumelages are evidence of intensified hunting by Humans and used to reconstruct Mammoth population dynamics. Anyhow, these interpretations continue controversial due to the taphonomic context of many sites are still debated. To regenerate the taphonomic setting of each site and the movement patterns of mammoths among sites, you have to analyse carbon, oxygen, and strontium isotope ratios in mammoth tooth enamel. The carbon isotopes of fossils vary with diet and local vegetation, oxygen isotopes vary with local climate, and strontium isotopes vary with local soil chemistry. If Pleistocene mammoths traveled together in small family groups, then mammoths from sites that represent family groups should have lower isotopic variability than mammoths from sites containing unrelated individuals. Low levels of carbon isotope variability were found to be the most diagnostic signal of herd/family group association. Even if the variability of oxygen and strontium isotope ratios proved less useful for identifying family group assemblages, these signals did provide information about the movement patterns of individuals among different sites. High levels of variability in each of the isotope systems at Clovis sites suggest that all of the sites examined represent time-averaged accumulations of unrelated individuals, rather than the mass deaths of family groups. In addition, analyses of the mean isotope values of Clovis mammoths show that although most Mammoths from Blackwater and Miami (2 of the fossil sites) had similar values, the values of Dent mammoths were significantly different. This demonstrates that the Dent mammoths exist to a separate population and suggests that Clovis mammoths did not routinely commence long distance (600 km) migrations.

https://www.cambridge.org/core/journals/...14F1857CE9

Mammuthus Wrote:Mammoth colour variation
[Image: laun.jpg]

For many years we have always believed that Woolly Mammoths are brown in colour. Thanks to the discovery of some beautifully preserved specimens many of them babies or juveniles (Dima, Lyuba and Yuka for example), palaeontologists have a much better idea of the genome of Woolly Mammoths.

By looking at the DNA of Woolly Mammoths scientests have begun to show that Woolly Mammoths could of had hair variation similar to Humans, having red (ginger), brunettes and possible blonde Mammoths.

Woolly Mammoths coats are specially designed for surviving harsh arctic weather. The coat makes up of 2 layers. The first layer contains long, guard hairs that are 6x thicker than human hair. This coat could grow to 1m when a Mammoth is fully-grown. The coat is designed to trap air, helping the Mammoth keep warm, the coat is similar to that of extant Musk-Ox another arctic animal. The second coat (inner coat/layer) consisted of hairs much shorter, softer and thinner hairs. Its purpose was the same as the first coat, to insulate the animal from freezing. There is a possibility this coat could of melted during spring, producing a much lighter summer coat.

The colour of the hairy coat could of varied as well, according the the genome researchers. There were brown Wooly Mammoths found, but there were some individuals that were reddish/orange is colour, other Mammoths were found to be a strawberry blonde colour. So if you were to travel back several thousand year and observe a herd of Mammoths, chances are they wouldn't all be brown in colour.

If you observe Mammoth cave-paintings there are a variety of different colours used for the Mammoths coat. This is another reason to suggest they did have a colour variation.

[Image: 8dbde4bf8365286f926ed2f6_baby-mammoth_6.jpg]
The hair of a strawberry blonde Mammoth.

Mammuthus Wrote:The reason Scientists want to resurrect the Woolly Mammoth
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The woolly mammoth went extinct at the end of the last ice age thousands of years ago, a victim of warming weather and hunting by prehistoric humans. But the mammoth — or rather something very much like it — may be resurrected if Dr. George Church has his way.

The Harvard geneticist started with a close relative, the Asian elephant, and is using a genetic engineering tool known as CRISPR in an effort to create a mammoth-like elephant capable of thriving in cold regions.

It's not a vanity project. Church thinks reintroducing the mammoth-like animal into parts the tundra could help curb climate change.

"By allowing cold resistant elephants or mammoths to repopulate the tundra," Church says, "they will punch down the snow in wintertime allowing cold air to come in, and in the summertime they'll knock down trees, which are very absorbent." This will help the dead grass start to grow, he explains, and slow the release of carbon from the soil into the atmosphere.

"When you simulate this with a real ecosystem in Siberia," he says, "the temperature drop is 20 degrees, which is really big deal in terms of delaying the release of carbon by melting."

So far Church's team has edited 15 key genes that will be needed to resurrect the mammoth, and he says they're well on the way to editing another 30-odd of the essential genes. Sounds like a mammoth effort.


SETA222 Wrote:" Woolly mammoth on verge of resurrection, scientists reveal
Scientist leading ‘de-extinction’ effort says Harvard team could create hybrid mammoth-elephant embryo in two years
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Woolly mammoth (Mammuthus primigenius), a model of an extinct Ice Age mammoth. Photograph: Andrew Nelmerm/Getty Images/Dorling Kindersley

The woolly mammoth vanished from the Earth 4,000 years ago, but now scientists say they are on the brink of resurrecting the ancient beast in a revised form, through an ambitious feat of genetic engineering.

Speaking ahead of the American Association for the Advancement of Science (AAAS) annual meeting in Boston this week, the scientist leading the “de-extinction” effort said the Harvard team is just two years away from creating a hybrid embryo, in which mammoth traits would be programmed into an Asian elephant.

“Our aim is to produce a hybrid elephant-mammoth embryo,” said Prof George Church. “Actually, it would be more like an elephant with a number of mammoth traits. We’re not there yet, but it could happen in a couple of years.”

The creature, sometimes referred to as a “mammophant”, would be partly elephant, but with features such as small ears, subcutaneous fat, long shaggy hair and cold-adapted blood. The mammoth genes for these traits are spliced into the elephant DNA using the powerful gene-editing tool, Crispr.

Until now, the team have stopped at the cell stage, but are now moving towards creating embryos – although, they said that it would be many years before any serious attempt at producing a living creature.

“We’re working on ways to evaluate the impact of all these edits and basically trying to establish embryogenesis in the lab,” said Church.

Since starting the project in 2015 the researchers have increased the number of “edits” where mammoth DNA has been spliced into the elephant genome from 15 to 45.

“We already know about ones to do with small ears, subcutaneous fat, hair and blood, but there are others that seem to be positively selected,” he said.

Church said that these modifications could help preserve the Asian elephant, which is endangered, in an altered form. However, others have raised ethical concerns about the project.

Matthew Cobb, professor of zoology at the University of Manchester, said: “The proposed ‘de-extinction’ of mammoths raises a massive ethical issue – the mammoth was not simply a set of genes, it was a social animal, as is the modern Asian elephant. What will happen when the elephant-mammoth hybrid is born? How will it be greeted by elephants?”

Church also outlined plans to grow the hybrid animal within an artificial womb rather than recruit a female elephant as a surrogate mother - a plan which some believe will not be achievable within the next decade.

“We hope to do the entire procedure ex-vivo (outside a living body),” he said. “It would be unreasonable to put female reproduction at risk in an endangered species.”

He added that his lab is already capable of growing a mouse embryo in an artificial womb for 10 days - halfway through its gestation period.

“We’re testing the growth of mice ex-vivo. There are experiments in the literature from the 1980s but there hasn’t been much interest for a while,” he said. “Today we’ve got a whole new set of technology and we’re taking a fresh look at it.”

“Church’s team is proposing to rear the embryo in an ‘artificial womb’ which seems ambitious to say the least – the resultant animal would have been deprived of all the pre-birth interactions with its mother,” said Cobb.

The woolly mammoth roamed across Europe, Asia, Africa and North America during the last Ice Age and vanished about 4,000 years ago, probably due to a combination of climate change and hunting by humans.

Their closest living relative is the Asian, not the African, elephant.

“De-extincting” the mammoth has become a realistic prospect because of revolutionary gene editing techniques that allow the precise selection and insertion of DNA from specimens frozen over millennia in Siberian ice.

Church helped develop the most widely used technique, known as Crispr/Cas9, that has transformed genetic engineering since it was first demonstrated in 2012. Derived from a defence system bacteria use to fend off viruses, it allows the “cut and paste” manipulation of strands of DNA with a precision not seen before.

Gene editing and its ethical implications is one of the key topics under discussion at the Boston conference.

Church, a guest speaker at the meeting, said the mammoth project had two goals: securing an alternative future for the endangered Asian elephant and helping to combat global warming. Woolly mammoths could help prevent tundra permafrost from melting and releasing huge amounts of greenhouse gas into the atmosphere.

“They keep the tundra from thawing by punching through snow and allowing cold air to come in,” said Church. “In the summer they knock down trees and help the grass grow.”

The scientists intend to engineer elephant skin cells to produce the embryo, or multiple embryos, using cloning techniques. Nuclei from the reprogrammed cells would be placed into elephant egg cells whose own genetic material has been removed. The eggs would then be artificially stimulated to develop into embryos.

Church predicts that age-reversal will become a reality within 10 years as a result of the new developments in genetic engineering.

https://www.theguardian.com/science/2017...scientists
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#35
DNA Mutations May Have Doomed the Woolly Mammoth

By Knvul Sheikh, Live Science Contributor | March 2, 2017 02:12pm ET

[Image: woolly-mammoths.jpeg?interpolation=lancz...ize=*:1400]
This mural at the American Museum of Natural History in New York City shows woolly mammoths near the Somme River.
Credit: Charles R. Knight

By the end of the ice age, the last remaining woolly mammoths had acquired so many genetic mutations that their numbers were practically guaranteed to spiral toward extinction, a new study has revealed.

Mammoths were once among the most common large herbivores that roamed across North America, Siberia and Beringia, a geographic area that once stretched from Siberia to the Canadian Yukon but is now mostly submerged under the Bering Strait. The giant beasts first appeared about 700,000 years ago. But, at the end of the last ice age, about 10,000 years ago, their population suddenly declined.

Scientists think a warming climate and the effects of human hunters led to the extinction of woolly mammoths on the mainland. Small populations continued to persist on isolated northern islands until they, too, vanished about 3,700 years ago. 

Researchers from the University of California, Berkeley, recently compared the existing genomes of two different mammoth specimens. One was a 45,000-year-old woolly mammoth found in northeastern Siberia, and the other was a 4,300-year-old mammoth from Wrangel Island, off the coast of Russia. The scientists found that the DNA of the Wrangel Island mammoth, which represents the last members of the species, had multiple harmful mutations that would have interfered with normal functions and compounded the difficulties of survival.

"It's sort of like a Greek tragedy that's written into the DNA of the poor mammoth," said lead study author Rebekah Rogers, an evolutionary geneticist at the University of North Carolina in Charlotte. "You look at this mammoth's DNA and you see all these bad mutations."

The findings suggest that in the end, as sea levels rose and cut off Wrangel Island mammoths, their small population and resulting inbreeding would have rendered the process of natural selection ineffective.

In larger populations, mutations that occur naturally are weeded out by competition, Rogers said. But with such a small population, there would have been no mechanism to prevent these mutations from being passed on to the next generation of mammoths. As such, harmful changes in the mammoth genome that deleted large chunks of DNA, or messed up how genes were read and translated, would have accumulated, according to Rogers.

By looking at which genes were affected by these harmful mutations, Rogers and her colleague, Montgomery Slatkin, a population geneticist at the University of California, Berkeley, were able to guess what functions or behaviors might have been affected as mammoth populations dwindled. The animals probably lost many olfactory receptors, which detect odors, as well as urinary proteins, the researchers found. This could have affected their social status and mate choice, Rogers said. The genome also revealed that the island mammoth had certain mutations that likely created an unusual translucent satin coat, as well as several other mutations with effects that scientists don't fully understand yet.

While the researchers said that their analysis was limited to one individual from the Wrangel Island mammoth population, they said they were fairly certain that this "genetic meltdown" would have occurred in the remaining mammoths as well.

"We would expect that if you got another mammoth from the island and you looked at its genome, that it would also have an excess of bad mutations," Rogers told Live Science. "They might not be the exact same mutations — some of them would be shared, and some of them might be different — but we would expect the same pattern." 

Other biologists agreed that the findings support a long-standing theory that genomes start unraveling as animal populations decline.

"It makes sense that the researchers would find an accumulation of deleterious mutations in a population that was very small," said Beth Shapiro, an evolutionary biologist at the University of California, Santa Cruz, who was not involved in the new study. "[This] reveals that it's not necessarily just a small population size that is potentially dangerous for populations but also the content of those genomes that's important."

The study offers a warning to conservationists, Shapiro said. If bad mutations start accumulating in small groups of isolated animals, it might not be sufficient to try and preserve endangered species after they have already undergone generations of inbreeding and genomic meltdown. Conservationists probably need to intervene much sooner, she said.

It might also provide an interesting twist to mammoth "de-extinction" experiments. If some mammoth genomes carry an overabundance of negative mutations, researchers need to carefully screen the genes before they are inserted into mammoth-elephant hybrid genomes, Rogers said. In fact, screening the mutations and testing what their functions are could also inform scientists about how the mutated genes affected mammoths just before they went extinct, she added.

Rogers and her colleagues detailed their analysis of the mammoth's genetic mutations in a study published online today (March 2) in the journal PLOS Genetics.

http://www.livescience.com/58088-woolly-mammoths-doomed-by-dna-mutations.html




Journal Reference:
Rogers RL, Slatkin M (2017) Excess of genomic defects in a woolly mammoth on Wrangel island. PLoS Genet 13(3): e1006601. doi:10.1371/journal.pgen.1006601

Abstract
Woolly mammoths (Mammuthus primigenius) populated Siberia, Beringia, and North America during the Pleistocene and early Holocene. Recent breakthroughs in ancient DNA sequencing have allowed for complete genome sequencing for two specimens of woolly mammoths (Palkopoulou et al. 2015). One mammoth specimen is from a mainland population 45,000 years ago when mammoths were plentiful. The second, a 4300 yr old specimen, is derived from an isolated population on Wrangel island where mammoths subsisted with small effective population size more than 43-fold lower than previous populations. These extreme differences in effective population size offer a rare opportunity to test nearly neutral models of genome architecture evolution within a single species. Using these previously published mammoth sequences, we identify deletions, retrogenes, and non-functionalizing point mutations. In the Wrangel island mammoth, we identify a greater number of deletions, a larger proportion of deletions affecting gene sequences, a greater number of candidate retrogenes, and an increased number of premature stop codons. This accumulation of detrimental mutations is consistent with genomic meltdown in response to low effective population sizes in the dwindling mammoth population on Wrangel island. In addition, we observe high rates of loss of olfactory receptors and urinary proteins, either because these loci are non-essential or because they were favored by divergent selective pressures in island environments. Finally, at the locus of FOXQ1 we observe two independent loss-of-function mutations, which would confer a satin coat phenotype in this island woolly mammoth.

Attached to this post:[Image: attach.png] Excess_of_genomic_defects_in_a_woolly_mammoth_on_Wrangel_island.pdf (1.62 MB)
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#36
Trapped! Woolly Mammoth Bachelors Often Met Disastrous Ends

By Laura Geggel, Senior Writer | November 2, 2017 12:00pm ET

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Help! A male woolly mammoth has fallen through the ice of a frozen lake.
Credit: Catmando/Shutterstock

Pity the male woolly mammoth: These poor creatures were more likely to meet their end in natural traps — falling through thin ice, tumbling into holes or getting stuck in mudflows — than their female counterparts, a new study finds.

Researchers made the discovery after determining the sex of 95 woolly mammoths (Mammuthus primigenius) whose remains were found across different parts of Siberia. In all, 66 of the specimens (69 percent) were male, while just 29 (31 percent) were female, they found.

The woolly mammoth lifestyle may be the cause of this skewed sex ratio. Inexperienced male mammoths were more likely to travel alone, away from the herd, so perhaps it's no surprise that these males were more likely to stumble into danger and die as a result, the researchers said. 

But there is an upside to these pachyderms' untimely deaths: Being buried in a natural trap — such as a bog, crevice or lake — tended to preserve their remains for thousands of years, allowing researchers to discover and study them.

"Most bones, tusks and teeth from mammoths and other ice age animals haven't survived," study researcher Love Dalén, a professor of evolutionary genetics at the Swedish Museum of Natural History, said in a statement. "It is highly likely that the remains that are found in Siberia these days have been preserved because they have been buried, and thus protected from weathering."

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A mammoth tusk on Wrangel Island, off the northeastern coast of Siberia, where mammoths didn't go extinct until about 3,700 years ago.
Credit: Patrícia Pečnerová

The discovery is part of a larger, long-term project researchers are undertaking to study the genomes of woolly mammoth populations. Some of the analyses required knowing the sex of the mammoths, and the results were unexpected, the researchers said.

"We were very surprised because there was no reason to expect a sex bias in the fossil record," lead study researcher Patrícia Pečnerová, a doctoral student of bioinformatics and genetics at the Swedish Museum of Natural History, said in the statement. "Since the ratio of females to males was likely balanced at birth, we had to consider explanations that involved better preservation of male remains."

The findings suggest that, like modern elephants, woolly mammoths had matriarchal hierarchies. As such, mammoth herds of young and female mammoths were likely led by an experienced adult female, the researchers said. Male mammoths, also like modern elephants, likely lived in bachelor groups or spent time alone, engaging in risky behavior, they said.

"Without the benefit of living in a herd led by an experienced female, male mammoths may have had a higher risk of dying in natural traps," Dalén said.

This discovery — that seven of every 10 mammoths found in natural traps were male — sheds light on the socioecology and behavior of these extinct animals, the researchers said. It's also a reminder that uncovered specimens don't necessarily represent a random sample of a species, they noted. 

The study was published online today (Nov. 2) in the journal Current Biology.

https://www.livescience.com/60845-male-mammoths-died-alone.html




Journal Reference:
Pecnerova  ´ et al., Genome-Based Sexing Provides Clues about Behavior and Social Structure in the Woolly Mammoth, Current Biology (2017), https://doi.org/10.1016/j.cub.2017.09.064

Highlights
•Paleogenomic sexing of 98 mammoth remains shows a significant skew toward males
•This implies a higher rate of preservation of male remains until the present day
•Inexperienced males more often dying in natural traps could explain this pattern
•The excess of male remains may thus be a result of the mammoth’s social structure

Summary
While present-day taxa are valuable proxies for understanding the biology of extinct species, it is also crucial to examine physical remains in order to obtain a more comprehensive view of their behavior, social structure, and life histories. For example, information on demographic parameters such as age distribution and sex ratios in fossil assemblages can be used to accurately infer socioecological patterns. Here we use genomic data to determine the sex of 98 woolly mammoth (Mammuthus primigenius) specimens in order to infer social and behavioral patterns in the last 60,000 years of the species’ existence. We report a significant excess of males among the identified samples (69% versus 31%; p < 0.0002). We argue that this male bias among mammoth remains is best explained by males more often being caught in natural traps that favor preservation. We hypothesize that this is a consequence of social structure in proboscideans, which is characterized by matriarchal hierarchy and sex segregation. Without the experience associated with living in a matriarchal family group, or a bachelor group with an experienced bull, young or solitary males may have been more prone to die in natural traps where good preservation is more likely.

Attached to this post:[Image: attach.png] Genome_Based_Sexing_Provides_Clues_about_Behavior_and_Social_Structure_in_the_Woolly_Mammoth.pdf (1.34 MB)
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#37
Mammuthus Wrote:If You Resurrect the Woolly Mammoth, Can You Still Call It a Woolly Mammoth?
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In the early 20th century, seeking riches, fur and its medicinal qualities, the people of Europe hunted the Eurasian beaver to near extinction. Clever scientists, though, had an idea of how to atone for their sins. The North American beaver, at least from the outside, seemed nearly identical. They would introduce this far-flung cousin to Europe in hopes that it would breed and help restore the population.

There was just one, fairly giant hitch: The two beavers were actually two separate species, and they were not genetically compatible. One had 40 chromosomes, the other had 48. They had unwittingly introduced an invasive species, and one that could not help them restore their own dwindling beaver population.

Today, as scientists mull using genetics to bring back everything from the long-gone woolly mammoth to the more recently smote heath hen, some have raised an intriguing question: If you raise an animal from extinction, is it really the same animal as the one that went extinct? And if it’s not, could there be consequences, just as early 20th century Europeans found with the North American beaver?


 
“A lot of people have discussed the technology, whether or not it’s actually possible to make a species no longer extinct, but we for the first time are thinking about the consequences of that,” Axel Hochkirch, a biologist at Trier University in Germany, told Gizmodo. “Even if we could completely restore the genome there would still be some differences in things like learned behavior, epigenetics and microbiome. That leaves a lot of uncertainties.”

There are multiple methods scientists are pursuing in order to accomplish bringing extinct species back to life. Scientists have already used cloning to restore, for a few brief minutes, the Pyrenean ibex, a method that relies on using the nucleus of the somatic cell of an extinct species and transferring it into the germ cell of a host species. Another method (the one being used to resurrect the woolly mammoth) involves using genome engineering to create a hybrid organism using available parts of the extinct species genome and genetic information from a closely related surrogate to fill in the gaps. Any way you slice it, in other words, a resurrected species would contain at least a small amount of genetic information from another species entirely.

In a set of “de-extinction guidelines” published last year by the International Union for Conservation of Nature, this fact led the body to go as far as calling them “proxy species” rather than “de-extinct.”

“Proxies of extinct species might constitute novel species by having unfamiliar ecological traits and being non-resident (having no recent evolutionary history) in a release area,” the guidelines explained.

Whether due to genetics alone or ecological and environmental changes since extinction, the guidelines warned that how a de-extinct species would behave in the wild could be hard to predict.

It continued: “A proxy species might become invasive if its establishment and growth causes damage to the environment, or to human economy or health. The negative effects of the proxy species might appear only long after its release into the wild.”

In a paper out this week in the journal Science, Hochkirch and colleagues argue that these considerations, combined with legal ambiguities of how a extinct species might be categorized, call for naming them something else entirely.

“There’s a lot of legal uncertainties,” he told Gizmodo. “The name of a species, for example, is quite crucial in conservation legislation. So it might be beneficial to name it something else, or at least to give it a clear label as a de-extinct species.”

If a species is endangered, for example, and then hundreds of a de-extincted version of it are released into the wild, you wouldn’t want those numbers to jeopardize the animal’s protected status. Likewise, if you were to release it, you might want it to have to undergo some of the same scrutiny that genetically modified organisms are subject to. In all accounts, he said, it could be important to distinguish a natural species from a de-extinct one in the eyes of the law.

Harvard geneticist George Church—the man behind the woolly mammoth project—disagreed though, that a de-extinct species would be something so entirely novel. He pointed to the gray wolf, which both went extinct in their native habitats but were eventually reintroduced.

“The environment had changed radically and the reintroduction went fine,” he told Gizmodo. “I’m not saying it’s always going to work out, but there are already test cases out there.”

The gray wolf reintroduction, in fact, did have an impact on the local ecology, which scientists are still studying, but much of that impact seems to be for the better, like a growing local beaver population. 

Church isn’t against calling the de-extinct animals something new, but he’s less certain it’s necessary. Changes to the environment like food sources can produce similar changes in animals that the IUCN guidelines raise and its rare that two members of a species are perfect copies to begin with. It also raises more complicated questions, like at what point an animal become a hybrid—if that woolly mammoth has 90 percent woolly mammoth DNA is it still a woolly mammoth, or 60 percent?

What is clear is that de-extinction raises many, many complicated questions even as it may provide a way to conserve threatened species.

“Success with this technology could be years or decades away,” Hochkirch said, “but its important to discuss these things now.”

http://gizmodo.com/if-you-resurrect-the-...1795967006
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#38
Mammoth moves: frozen cells come to life, but only just

March 12, 2019

[Image: thefrozencar.jpg]
The frozen carcass of a female mammoth on display in Yokohama a few years ago.

A team of scientists in Japan has successfully coaxed activity from 28,000-year-old cells from a frozen mammoth implanted into mouse cells, but the woolly mammal is unlikely to be walking among us soon.

The project by an international team took cell nuclei from a well-preserved mammoth discovered in 2011 in Siberian permafrost and placed them into several dozen mouse egg cells.

Of those, five displayed the biological reactions that happen just before cell division begins, said Kei Miyamoto, a member of the team at Kindai University in western Japan.

None, however, produced the actual cell division needed for a mammoth rebirth, the researcher told AFP.

"This suggests that, despite the years that have passed, cell activity can still happen and parts of it can be recreated," he told AFP.

"Until now many studies have focused on analysing fossil DNA and not whether they still function," he added.

The research—published Monday in the journal Scientific Reports—doesn't provide much hope for Jurassic Park-style resurrection of long-extinct species just yet, he cautioned.

"We have also learned that damage to cells was very profound."

"We are yet to see even cell divisions. I have to say we are very far from recreating a mammoth."

The university has worked with other Japanese and Russian institutes to study and to possibly clone the mammoth and plans to study alternative methods to bring the prehistoric giant back to life.

"We need new technology, we want to try various approaches," Miyamoto said.

Read more at: https://phys.org/news/2019-03-mammoth-fr...e.html#jCp




Journal Reference:
Kazuo Yamagata et al. Signs of biological activities of 28,000-year-old mammoth nuclei in mouse oocytes visualized by live-cell imaging Scientific Reports volume 9, Article number: 4050 (2019)

Abstract
The 28,000-year-old remains of a woolly mammoth, named ‘Yuka’, were found in Siberian permafrost. Here we recovered the less-damaged nucleus-like structures from the remains and visualised their dynamics in living mouse oocytes after nuclear transfer. Proteomic analyses demonstrated the presence of nuclear components in the remains. Nucleus-like structures found in the tissue homogenate were histone- and lamin-positive by immunostaining. In the reconstructed oocytes, the mammoth nuclei showed the spindle assembly, histone incorporation and partial nuclear formation; however, the full activation of nuclei for cleavage was not confirmed. DNA damage levels, which varied among the nuclei, were comparable to those of frozen-thawed mouse sperm and were reduced in some reconstructed oocytes. Our work provides a platform to evaluate the biological activities of nuclei in extinct animal species.

https://www.nature.com/articles/s41598-019-40546-1.pdf
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#39
Is there a way to put/copy the description of the mammoth to the Ice age Discoveries Thread ? IT is the main subject of the thread and would an outstanding info for the browsers !

Thanks !
Just a normal guy who want to learn things !
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