2018 Fossil Find May Aid Revival of Extinct Prehistoric Species

Perfectly preserved woolly mammoth DNA discovered in Siberia could help revive the species, scientists told The Independent.

Researchers have reassembled the genome of a 52,000-year-old woolly mammoth using fragments of fossil DNA, the first of its kind discovered in Siberia. It’s a breakthrough that brings researchers one step closer to bringing the extinct giants back to life.

The study, recently published in the journal Cell, presented the reconstruction of woolly mammoth chromosomes, as well as the structure of the cell nucleus where DNA and proteins are organized into genes.

Most copies of ancient genomes discovered in fossils so far consist only of tiny, jumbled fragments of DNA.

But the 52,000-year-old mammoth’s genome could be reconstructed in detail because the animal was freeze-dried shortly after it died. Scientists tested dozens of mammoth DNA samples for five years to reconstruct the giant animal’s genome before coming into possession of the unusually well-preserved sample of a mammoth fossil excavated in northeastern Siberia in 2018.

This remarkable fossil preserved much of the physical integrity of the chromosomes, including the proteins in contact with the genes they control, the researchers said.

In this way, scientists can better understand the organization of the mammoth’s genome and find out which genes were active at different times in the animal’s life.

“This is a new type of fossil, and its scale exceeds that of disparate fragments of ancient DNA,” said study co-author Erez Lieberman Aiden of Baylor College of Medicine.

The researchers then created a map of the mammoth genome using the genomes of today’s elephants as a template. The findings showed that woolly mammoths had 28 chromosomes, the same number as today’s Asian and African elephants.

The scientists were also able to find genes in the mammoth’s skin cells, revealing how the giant mammal developed its woolliness and cold tolerance.

“For the first time we have woolly mammoth tissue for which we know approximately which genes were active and which genes were inactive,” said Marc A Marti-Renom, another author of the study.

“This is an extraordinary new type of data and is the first assessment of cell-specific gene activity in any sample of ancient DNA,” said Dr. Marti-Renom.

Woolly mammoths roamed Earth’s northern hemisphere for over half a million years and began to disappear at the end of the last ice age, about 10,000 years ago.

Scientists believe that a combination of factors, including overhunting by early humans and climate change led to their final extinction around 4,000 years ago.

“These results have obvious consequences for today’s efforts to learn how the woolly mammoth went extinct,” said M Thomas Gilbert, another author of the study. The researchers hope that the methods used in the latest study could be used to analyze other ancient DNA samples, including those of Egyptian mummies, to reveal their appearance and lifestyle.