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The ancient DNA of woolly mammoths suggests they roamed the Earth much more recently than we thought.
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The ancient DNA of woolly mammoths suggests they roamed the Earth much more recently than we thought.

Synthesis of genetic and fossil evidence


A team from the University of Minnesota collected small cores of permafrost sediments in 2010. University of AlbertaFrom Gold minesThey were located in central Yukon’s Klondike Region. They were kept in cold storage until paleogeneticists at The McMaster Ancient DNA CentreNew genomics techniques were used to better understand the Global extinctions of megafauna occurred in North America 12700 years ago.

These tiny sediment samples contain a wealth of environmental DNA from many species that lived in those environments for thousands of years. These genetic microfossils originate from all components of an ecosystem — including bacteria, fungi, plants and animals — and serve as a time capsule of long-lost ecosystems, such as the mammoth-steppeIt was lost around 13,000 years ago.

An explanation of how these ecosystems were restructured so dramatically and why large animals seem the most affected by this shift is available. Since the 18th century, scientific debate has been an active area of scientific discussion.

Now, environmental DNA can be used to fill in the gaps that have sparked this debate.

Ancient DNA, cutting-edge technologies

More than 99.99% of environmental samples contain bacteria, fungal, or unidentifiable DNA. We wanted to be able to selectively recover the DNA of animals and plants from the past that would allow us to better understand the mammoth-steppe collapse.

For my Doctoral researchI was part a team that created a A new technique for extracting, isolating, sequencing and identifying tiny fragments ancient DNA from sediment.

These DNA fragments were analysed to track the changing cast of animals and plants that have lived in central Yukon for the past 30,000 year. We found evidencefor the survival of woolly mammoths in the Klondike region and horses in the Klondike Region, some 3000 years later than expected.

Then we We have expanded our analysis21 permafrost cores previously collected from four locations in the Klondike area that date back between 4,000 and 30,000 years ago are included.

Modern technologies allow us to identify which organisms the genetic microfossils come from. We also have the ability of identifying the origins of a set genetic microfossils from other organisms. They were also able reassemble those fragments into genomes to study their evolutionary histories — solely from sediment.

Synthesis of genetic and fossil evidence

Synthesis of dated bones and ancient environmental DNA, as well as archaeological sites in Yukon or Alaska.
(Tyler J. Murchie)

Tremendous environmental change

The Pleistocene–Holocene transition took place around 11,700 years ago.The period saw tremendous changes all over the globe. In Eastern Beringia is the former Eurasian landbridge and unglaciated Yukon and Alaska regions.This period saw the collapse mammoth-steppe biomegradually replaced with the boreal forestAs we know it today.

This resulted in the extinction of iconic megaherbivores from the Ice Age, such as the Woolly mammoth, Yukon horse, steppe bisonTogether with predators such the American scimitar cat Beringian lion, among others.

We found ancient environmental DNA among a wide range of ancient fauna. This includes woolly mammoths as well as horses, steppe bisons and caribou..

We were also able observe how ecosystems changed with the rise in woody shrubs about 13,500 years ago and how this was correlated with a decrease of DNA from woolly mammals, horses, and steppe bison. We were able to observe four main findings from this rich dataset.

  1. There was a remarkable consistency in the signal between the sites, which suggests that our data was representative for ecological trends in the area.

  2. The decline in woolly mammoth DNA was before the Bølling–Allerød warmingA warm period at the beginning of the last Ice Age suggests that megafaunal loss may have been staggered.

  3. Forbs (herbaceous flowering plants)Together with grasses, they make up a large part of the mammoth steppe ecosystem.

  4. There is a steady signal of woolly mammoths and Yukon horses persisting into the Holocene as much as 7,000 year after their disappearance from fossil record.

Comparing equid genomes reconstructed from sediments and bone

An evolutionary tree that shows the relationship between horses and their relatives, using genomes reconstructed with bones and sediment.
(Tyler J.Murchie), Author provided

Our genetic reconstructions are paired with other records and suggest that the transition out from the last glacial period was more gradual than dated bones would suggest.

For example, Mammoths may have experienced a decline in local population abundance many years before other megafauna. This could be correlated with the first Some controversial evidenceThere are many people living in the area. Further, In refugia (habitats that support the existence an isolated population), grassland grazing livestock may have survived for thousands of year.Despite the environmental shift.

Along with humans, woolly mammoths are also found

Our data suggests that horses, woolly mammoths, and possibly even 5,700 years ago, may have survived the Klondike’s disappearance. Local fossil records for 7,000 years. It is possible. Antiquity of environmental DNA that can withstand erosion and re-depositionThere are many factors that could cause a mix of the genetic signals of different times periods. Therefore, we need to be careful in our interpretations.

There was no evidence that mammoths survived into the mid-Holocene, until recently. However, studies have shown that mammoths were able to survive until recently. 5,500 4,000Years ago, Arctic islands were home to many.

Researchers at the Centre for GeoGenetics, CopenhagenEvidence has been found that Alaskan horses and mammoths survived the end of their lives, as far back as 1898. 7,900 years ago. They also discovered evidence that mammoths survived in Siberia as recently as 3900 years ago. Woolly rhinocerosAt least 9,800 years ago.

Steppe bison were thought to have disappeared and be replaced by the American bisonAlso, during the Pleistocene it was found that they survived as recently as maybe just 400 years ago. We were able watch The presence of distinct genetic lineages for both woolly mammoths (and steppe bison)The same sediment samples were found, suggesting that these animals may have lived in different areas.

Evidence is mounting that many megafauna from the Ice Age may have survived into recorded human history. They were found in the north during the Ice Age. Bronze AgeWhile the builders worked on it, Pyramids of Egypt.

illustration of a woolly rhinoceros
Researchers from Denmark discovered evidence that woolly rhinoceroses existed in Siberia as early as 9,800 years ago.

Genetic archives of our ecological history

The complexity of environmental DNA methods to study microfossils from ancient genetics is increasing, revealing how much information is hidden in sediments.

Permafrost is a great way to preserve ancient DNA. Permanently frozen ground melts and thaws with a warming ArcticSo too, will the genetic material contained within and the evolutionary mysteries they once held.

The boundaries of science fiction are being pushed by advances in paleogenetics. Who knows what hidden evolutionary information may remain in ordinary sediments, or hidden in microfossils that contain ancient DNA?


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