Researchers have recently made a groundbreaking discovery by reconstructing the 3D structure of ancient genetic material for the first time from a 52,000-year-old freeze-dried mammoth. This discovery has allowed scientists to map the mammoth’s genome with incredible accuracy, as well as detect traces of past gene activity in the creature’s cells.
Typically, ancient DNA appears in short, scattered snippets, which have been used in the past to identify new species, rewrite the history of horse domestication, and understand the extinction of various creatures. However, the latest research has taken this a step further by capturing an ordered stack of intact chromosome structures, unlike previous fragmented efforts.
The mammoth sample, taken from near the mammoth’s ear, preserved well due to spontaneous freeze-drying after being blanketed by permafrost when it died. The low temperature of the tundra slowed the motion of its molecules, preventing the DNA fragments from dispersing and maintaining chromosome structures as tiny as 50 nanometers across.
To recover the precise features of the mammoth’s chromosomes, researchers used a modified version of a procedure called Hi-C to map sections of DNA that were in contact with each other. The mammoth’s genetic material clustered into 28 pairs of chromosomes, the same number found in living Asian and African elephants, indicating the method produced reliable results.
By comparing the woolly mammoth’s chromosomal compartments with those of its closest living relative, the Asian elephant, researchers identified genes responsible for the mammoth’s hairiness and cold resistance. For example, the inactivity of the EGFR gene in the mammoth but its activity in the Asian elephant explains the mammoth’s iconic hairiness.
Additionally, the study demonstrated the potential of using this technique on other well-preserved fossils to extract valuable genetic information. By experimenting on various types of beef, researchers found that fresh meat lost its chromosomal structure after three days at room temperature, while dehydrated meat retained its structure for over a year, surviving harsh conditions like being run over by a car or dipped in acid.
The researchers are optimistic about the future implications of this study, suggesting that the modified Hi-C protocol could work on specimens up to two million years old. This technique could lead to a more precise understanding of ancient genomes, allowing for the analysis of new species and generating insights into evolutionary trees and environmental adaptations.
Overall, this groundbreaking study opens up new possibilities for exploring the biology of extinct species and may pave the way for future discoveries in the field of paleogenomics. The researchers hope that their work will inspire other scientists to uncover more hidden treasures like the “Chris Waddle” mammoth and advance our understanding of ancient life forms.
