Million-Year-Old DNA Rewrites the Mammoth Family Tree
Imagine an elephant, but quite tall and heavy and with a long tusk. He is a Colombian giant, a stunted animal that roamed much of North America during the recent ice age.
When it comes to the giant family tree, it has long been believed that the Columbian mammoth evolved earlier than the smaller, giant breast of chagier wool. But now, using DNA that is more than a million years old – the oldest ever recovered from a fossil – researchers have turned that notion on its head: they found that the Columbian mammoth is actually a hybrid of woolly mammoth And is not already recognized. Great dynasty.
These were the results Published on Wednesday in the journal Nature.
Are mammoths Is depicted in many cave paintingsA reflection of their importance as a source of food, skin, and bone during the Pleistocene. During the last ice age, whatever is in America today, humans living in it will mainly be Faced Columbian mammoth, Said Love Dalen, a paleontologist at the Center for Palaeogenetics in Stockholm. “It is an iconic species of the last ice age,” he said.
Fossil remains of mammals, especially those Preserved in great detail, Can shed light on the way these animals live and die. But analyzing the genetic code of an ancient creature – recovering its DNA and re-incorporating it into a genome – opens up vast new research possibilities, David Diaz-del-Molino, another antibacterial at the center of Palaeogenetics. “You can track the origin of the species.”
Dr. Dalan and Drs. A team of researchers, including Dez-del-Molino, have recently set out to do so using three giant molars in northeast Siberia.
These teeth are older – around 700,000 years, 1.1 million years and 1.2 million years – and they are also impressive to look at, Drs. Dalan said. “They are shaped like milk cartons.”
Researchers started with the exercise of a small dentist by removing a little material from the inside of each tooth. They then used chemicals and enzymes, followed by washing protocols, to separate the resulting DNA into the tooth powder.
Most of the DNA he extracted contained a few tens of base pairs long. This is expected because it is difficult to pass time on DNA molecules. Bacteria and enzymes cut DNA after an organism dies, and the process of burying water and cosmic rays in the permafrost continues even after one sample.
Patricia Pecanarova, an evolutionary biologist at the University of Copenhagen and a researcher on the team, said that very soon the base began as millions of people. “DNA is very fragmented,” he said.
But before everything can be digitally put back together, it is necessary to deconstruct each sample, said Tom van der Valk, another team member and a bioinformatician in the science lab in stock samples. That’s because the DNA of plants, bacteria, and humans are wildly penetrating into fossils, he said. “A large part of our data does not come from mammoths.”
To interleave DNA, the team compared scenes with genetic code from an African elephant, a close relative of Mammoth. They discarded anything that did not match. In addition, they throw out sequences that match the human genome.
After removing the non-mammoth DNA, the team was left with between 49 million and 3.7 billion base pairs in each of their three samples. (The giant genome is approximately 3.2 billion base pairs, slightly larger than the human genome.) Researchers compared their data with African elephant DNA a second time, allowing them to place all of their DNA fragments in the correct order.
This massive DNA breaks the record of the oldest DNA ever held by one Horse specimen around 700,000 years old, Morton E. Allantoft is an evolutionary biologist at Curtin University in Perth, Australia, who was not involved in the research. “This is the oldest DNA that has ever been authentically identified,” he said.
When the researchers looked at the three genomes they reconstructed, the oldest stood out. “Gnome looked weird,” Dr. Dalan said. “I think it is likely that it is a different species.”
It was a shock: Researchers have long believed that only mammals in Siberia had a single lineage that gave birth to woolly and Columbian mammals. This discovery suggests that a previously undiscovered giant dynasty also existed.
“It’s a huge surprise,” Dr. Delane said. “It is completely unexpected from paleontology that there will be a second lineage.”
The team then compared three genomes to the genetics of the Columbian mammoth, which roamed most of North America as recently as 12,000 years ago. The goal was to determine how, if at all, these two species were related.
They found strong evidence that the woolly mammoth and this new unknown lineage formed the Colombian mammoth of a hybrid species.
Dr. Van der Valk said that no one knows where and how long this new giant dynasty is. “It would be absolutely amazing if we could get some more specimens of this lineage.”
Dr. Dallen said there is also a possibility of reconstructing old and outdated DNA. We will not recreate Jurassic Park, he said, but theoretical models suggest that DNA can live for a few million years. “I don’t think we’re on the border yet.”