52,000-year-old mammoth unveils secrets, scientists reconstruct genome

The well-preserved body of a woolly mammoth from 52,000 years ago has allowed scientists to reconstruct its three-dimensional genome for the first time. The samples contained more information than previously thought possible.

The latest research results, published on Thursday in the journal Cell, indicate that ancient DNA samples may contain more information about the past than previously assumed. All thanks to the mammoth found in Siberia. Scientists emphasize that it was preserved in excellent condition due to the dry and frosty winters there.

While analyzing the skin samples, scientists discovered that they were virtually intact. Further magnifications revealed that the chromosomes in each cell were still organized into clear structures, giving experts insight into which genes were active at the time and which were switched off during the mammoth’s life.

Knowing the structure of the genome, you can figure out which genes were active in that particular animal at the moment that it died and which genes were repressed, said Marc A. Marti-Renom, co-author of the study and professor at the National Center for Genomic Analysis in Barcelona, as quoted by The Washington Post.

Olga Dudchenko, a research assistant at Baylor College of Medicine who participated in the study, admits that until now, it wasn't known that ancient samples could be preserved in such good condition. Most of them were significantly fragmented because DNA begins to degrade after an organism's death. While ancient DNA in the sample collected from the Siberian mammoth has fragmented over the last 52 millennia, it was a relatively minor process in the skin cells.

The authors discovered similar chromosome structure preservation in another woolly mammoth sample. This piece of skin was taken from a 39,000-year-old mammoth named Yuka, which is considered one of the best-preserved mammoths ever found.

The authors suspect that chromosome arrangements were preserved in a process known as vitrification, in which all material components are frozen in time under appropriate temperature conditions.

Research indicated that the mammoth had 28 pairs of chromosomes, similar to its closest living relative, the elephant. Using information about the location of chromosomes in the cells, the authors could detect genes responsible for the differences between the mammoth and the elephant. This includes genes that lead to hair growth and the mammoth's ability to maintain warmth in a cold environment.

In addition to advancements in genomics, these research findings may play an essential role in animal conservation efforts.

To assess how poorly or how well species are doing in terms of genetic diversity and their overall genetic health, it’s important to understand … what is ‘natural’ for them, said Patrícia Chrzanová Pečnerová, an assistant professor of evolutionary genetics at the University of Copenhagen, who was not involved in the study.

Scientists aim to answer the question of what the mammoth population looked like before the human species began hunting them or before climate changes occurred. Eriona Hysolli, head of biological sciences at Colossal Biosciences, a company working on reintroducing a version of the woolly mammoth to the Arctic, stated that the three-dimensional chromosome structures found by the authors may reveal genome features that could have been significant in the process of mammoth extinction.