How DNA is preserved in archaeological sediments for thousands of years

The analysis of ancient DNA preserved in sediments is an emerging technology allowing for the detection of the past presence of humans and other animals at archaeological sites. Yet, little is known about how DNA is preserved in sediment for long periods of time. Scientists have now shed light on the matter by isolating DNA from solid blocks of undisturbed sediment that are embedded in plastic resin. The study reveals that ancient human and animal DNA is concentrated in small 'hot spots', particularly in microscopic particles of bone or feces. Micro-sampling of such particles can recover substantial amounts of DNA from ancient humans, such as Neanderthals, and other species and link them to archaeological and ecological records at a microscopic scale.