Shotgun and capture enriched metagenomic data from 2 million year old geological sediments. A 2-Million-year-old ecosystem in Greenland uncovered by Environmental DNA

Late Pliocene and Early Pleistocene epochs 3.6 to 0.8 million years (Ma) ago1 had climates resembling those forecasted under future warming2. Paleoclimatic records show strong polar amplification with mean annual temperatures of 11–19 °C above contemporary values3,4. The biological communities inhabiting the Arctic during this time remain poorly known because fossils are rare5. Here, we report the oldest ancient environmental DNA (eDNA)6 record to date describing the rich plant and animal assemblages of the Kap København Formation in North Greenland dated to around 2 Ma. The record shows an open boreal forest ecosystem with mixed vegetation of poplar, birch, and thuja trees as well as a variety of Arctic and boreal shrubs and herbs many of which had not previously been detected at the site ​​from macrofossil and pollen records. The DNA record confirms the presence of hare and mitochondrial DNA from animals including mastodons, reindeer, rodents and geese, all ancestral to their present day and Late Pleistocene relatives. Marine species including horseshoe crab and green algae support a warmer climate than today. The ecosystem reconstructed has no modern analogue. The survival of such ancient eDNA likely relates to its binding to mineral surfaces. Our findings open new chapters in genetic research, demonstrating that it is possible to track the ecology and evolution of biological communities 2 Ma years into the past using ancient eDNA.