Overview
- Researchers analyzed 13 ground‑squirrel coprolites recovered from frozen burrows in the Klondike and found environmental DNA spanning roughly 17,000 to about 700,000 years that allowed reconstruction of over 18 mitochondrial genomes, including multiple woolly mammoth sequences.
- Genetic results show DNA from plants, insects, microbes and large animals such as mammoths, horses, steppe bison and big cats, which the authors interpret as material squirrels collected in burrows while preparing for hibernation.
- The coprolites also revealed a previously unrecognized ground‑squirrel lineage more closely related to the long‑tailed Urocitellus undulatus that is today found in parts of Eurasia rather than to Yukon Arctic ground squirrels.
- Authors dated some samples using volcanic‑ash layers and focused on mitochondrial genomes, but peer reviewers and the team note key uncertainties from possible surface contamination, vertical leaching into pellets, and limits of mitochondrial data compared with nuclear genomes.
- The researchers plan further analyses of the mammoth sequences, will make the data public, and say the findings both open a new paleo‑archive for studying past ecosystems and highlight the risk that permafrost thaw and mining will destroy similar buried records.