A prehistoric creature has just offered a startling discovery, as a new research study reveals that scientists mapped the three-dimensional architecture of a woolly mammoth’s genome using fossilized remains. This marks the first time that science has been able to completely copy the DNA of an ancient animal from a fossil.
The paper, published July 11 in the journal Cell, is the culmination of a six-year study by an international community of scientists. The completion of the genome map represents a “new type of fossil, a fossil chromosome,” Erez Lieberman Aiden, a professor of molecular and human genetics at Baylor College of Medicine and one of the study’s co-authors, told The New. York Times. This fossil may help provide more scientific insights in the future.
What did the scientists do?
The fossilized remains in question were from a 52,000-year-old woolly mammoth found in remote Siberia. The mammoth was “perfectly freeze-dried by nature, parts of its fur remaining intact,” the Washington Post said, possibly due to the region’s harsh winters. As a result, the mammoth “probably entered a dehydrated state immediately after death, protecting it from colonization by fungi and bacteria.”
Using one of these fur samples, the scientists “studied a small sample of skin from the back of the mammoth’s ear,” Post said. During an examination of the hair follicles, it was found that “the chromosomes in each cell were still organized into clear territories, giving experts insight into which genes were turned on and off while the mammoth was alive.”
With this knowledge, combined with the quality of the sample, the scientists were able to “extract the DNA and use a technique known as Hi-C to reconstruct the three-dimensional structure of all 28 mammoth chromosomes – the creature’s entire genome disappeared”. said NPR. This was no easy task; the mammoth genome has more than 4 billion DNA base pairs. The human genome, by comparison, has only 3 billion.
Scientists were “able to assemble the genome of a woolly mammoth just as 25 years ago people were excited to assemble our own genomes for the first time,” Aiden said. Now this can be done “for animals that were long gone. This is definitely a milestone.”
How could this discovery be useful in the future?
The discovery “opens up huge new opportunities to explore the biology of extinct species,” Adrian Lister, a paleontologist at London’s Natural History Museum, told Scientific American. It is an “amazing study”.
One of the most obvious potentials for the study is that it could open the floodgates for similar genetic information to be gleaned from fossilized remains. “Widespread use of the technique could generate more accurate ancient genomes and allow the analysis of new species,” Juan Rodríguez, a geneticist at the University of Copenhagen and co-author of the study, told Scientific American. Piecing together ancient DNA often requires a lot of guesswork, but “the new 3D structural analysis circumvents these hurdles,” meaning that “future work could flesh out evolutionary trees” or “examine how organisms adapted to environments their changing, producing knowledge for modern conservation efforts.”
These conservation efforts could include assessing “how badly or how well species are doing in terms of genetic diversity and their overall genetic health,” Patrícia Chrzanová Pečnerová, an assistant professor of evolutionary genetics at the University of Copenhagen, told the Post. The progress of the woolly mammoth is a good example of this, because “if we want to be able to understand what is natural, we have to go back to the past.”
The researchers “strongly believe that this will not only apply to the mammoth or this particular mammoth,” Olga Dudchenko, an assistant professor of molecular and human genetics at Baylor College of Medicine and another co-author of the study, told CNN. Instead, this discovery is “essentially opening up a new field that has tremendous potential.”