Ice Age Mammoth and Horse DNA Found in Soil Samples Left in Freezer - Gizmodo

An analysis of DNA locked away in frozen soil samples reveals that charismatic species like woolly mammoths and the wild horses of the Yukon stuck around for longer than previously believed.

Unlike traditional DNA samples, which might be taken from bone or hair of some organism, soils (even ancient ones) contain environmental DNA, which is genetic material locked away in the microscopic residue animals leave as they move through an environment.

The ice-cold cores from Klondike were later found in a McMaster University freezer by Tyler Murchie, an archaeologist specializing in ancient DNA at the university, who began to reinvestigate them.

(The team used radiocarbon dating of plant material in the soil samples to determine their ages.) But the animals didn’t vanish quickly; woolly mammoth and North American horse DNA remain present in the samples until as recently as 5,000 years ago, in the mid-Holocene, some 8,000 years later than the animals were once thought to have gone extinct.