In Whitehorse, Yukon Territory, Canada, a groundbreaking discovery has reshaped our understanding of the ancient woolly mammoths that roamed North America. Uncovering a mammoth tooth dating back 216,000 years along the Old Crow River, researchers have identified this specimen as the oldest woolly mammoth fossil ever found on the continent.
This remarkable find challenges long-standing beliefs regarding the arrival of woolly mammoths in North America. Previously, it was thought that these majestic creatures migrated to the continent between 120,000 and 100,000 years ago. However, the discovery of this ancient tooth suggests that woolly mammoths may have been present much earlier, raising questions about the traditional theory of mammoths crossing the Bering Strait during the last Ice Age.
Led by researcher Camilo Chacón-Duque from the Centre for Palaeogenetics at Stockholm University, a study published in the journal Molecular Biology and Evolution unveils the significance of this discovery. The Old Crow mammoth, as it is now known, stands out as the oldest North American mammoth fossil identified with confidence as a woolly mammoth, setting it apart from other similar-age specimens found in the region.
The method used to determine the age of the Old Crow mammoth, molecular clock dating, relies on analyzing genetic mutations in DNA to estimate the specimen’s age. In this case, the extraction of DNA from the mammoth tooth allowed researchers to precisely pinpoint its age beyond the conventional radiocarbon dating limit of 50,000 years. By combining this innovative dating technique with geological data, the team achieved a highly accurate age estimate that aligns with geological evidence.
This groundbreaking approach not only revolutionizes fossil dating but also offers insights into the genetic secrets of ancient mammoths. The DNA extracted from the Old Crow mammoth reveals long-lost genetic diversity, shedding light on how woolly mammoths adapted to various environmental changes over hundreds of thousands of years. This deep-time DNA analysis provides valuable information on mammoth evolution and diversification across different climates and ecosystems in the Northern Hemisphere.
As researchers continue to delve into mammoth DNA, they uncover patterns of genetic diversity that point to how different mammoth populations responded to environmental pressures. During warmer periods, mammoth populations retreated to isolated refugia, only to expand again during colder phases, painting a vivid picture of how these majestic creatures thrived in the harsh conditions of the Ice Age.