About 52,000 years ago, a woolly mammoth perished in the Siberian tundra, where its body froze instantaneously in the extreme cold, resulting in a remarkable preservation of its DNA. In 2018, an international expedition unearthed the remarkably well-preserved remains of the mammoth, extracting skin samples from its head, ears, and hair.
Researchers successfully reconstructed the woolly mammoth genome in three dimensions with nanometer precision, a groundbreaking feat detailed in a publication in Cell magazine. This advancement opens up the opportunity to delve into DNA structures that were previously inaccessible, even in modern individuals.
Prior efforts to piece together ancient DNA were limited to incomplete puzzles due to the scarcity of genetic material fragments available to scientists. However, with the innovative Paleohi-C reconstruction method, researchers managed to assemble the entire ancient genome in a 3D format.
The scientific team employed modern techniques to analyze the interactions among various genetic segments within the cell nucleus, enabling the creation of a 3D model of the genome. By comparing the active genes of the mammoth to those of its closest contemporary relatives, the Asian elephants, researchers discovered significant differences.
During the study, around 820 genes unique to the mammoth and elephant were identified, with 425 genes active solely in mammoths. One gene found to be shared with elephants but not active in Inuits from Nunavik might be linked to cold adaptation. Additionally, a gene responsible for profuse wool growth in mammoths was found to be inactive.
Further analysis revealed that the structural integrity of the mammoth genome was maintained through a dehydration process akin to the preservation techniques used for products. The DNA of the mammoth likely endured due to a state called “chromo-winding,” allowing it to survive over millennia.
Future research endeavors aim to investigate gene expression in other mammoth tissues and compare them with those of modern elephants. These studies not only promise a deeper comprehension of evolution but also hold potential for ongoing efforts to resurrect woolly mammoths.