Beef jerky and some woolly mammoths have at least one thing in common: Drying turns their DNA into super-tough glass. This glassy DNA is so stable that it preserved the three-dimensional structure of chromosomes in one woolly mammoth for 52,000 years, researchers report. The find gave researchers an unprecedented look at the extinct animal’s genetic instruction book, or genome, even revealing genes that were turned on and off before the mammoth died.
The detailed survey of the mammoth genome was made possible after an international team of scientists figured out how to adapt a technique dubbed Hi-C to examine ancient DNA. This was a significant breakthrough, as DNA usually crumbles over time, making it hard to retain the shape of chromosomes. Previously, Hi-C was used for examining the 3-D structure of DNA in fresh, intact samples.
The experiments conducted on ancient samples often failed initially, but the team continued to work on developing a new version of the technique called PaleoHi-C. This iterative process of research, full of failures, eventually led to success. The team’s persistence and collaborative effort with over 50 scientists from different areas of expertise were crucial in achieving their goals.
After years of partial success and failure, the team managed to obtain skin from the head of a woolly mammoth that died 52,000 years ago. The mammoth was freeze-dried and preserved in permafrost, which led to the preservation of its DNA in a tough molecular structure called chromoglass. The glassy DNA locked the mammoth’s chromosomes into place, allowing researchers to count the number of chromosomes and examine the gene activity in mammoths compared to elephants.
By studying the ancient DNA of mammoths, researchers found genes that were active in mammoths but not in elephants, shedding light on the differences in their traits such as skin and hair growth. This research also extended to a second mammoth that was killed by a saber-toothed tiger about 39,000 years ago, revealing similar preservation of DNA structures in chromoglass form.
The findings have opened up new possibilities for researchers studying ancient DNA, providing a novel approach to examining genetic material that was previously thought to be too degraded to analyze. This breakthrough has the potential to address longstanding questions and problems in the field of genomics, offering a new direction for future research.
In conclusion, the preservation of woolly mammoth DNA through freeze-drying technology has allowed scientists to unlock valuable insights into the genetic makeup of these ancient creatures. The discovery of chromoglass DNA structures has paved the way for new opportunities in ancient DNA research, offering a fresh perspective on how extinct organisms functioned and evolved over time.
