On the origins of DNA in sediments

Living organisms are constantly shedding DNA in to their environment. Some portion of that DNA may
eventually become bound to sediments, buried, and later recovered in an ancient DNA laboratory. Many
studies have used such ancient DNA from sediments to study past ecosystems, or to zoom in on the
population genetics of specific organisms. The source, the specific route that this DNA took on its way to
adhering to a mineral particle, and the subsequent fate of that mineral particle are critically important to
the interpretation of the genetic results, yet in many studies are unknown. Here we examine data from
several studies to investigate the source of ancient DNA in lake, terrestrial, and archaeological
sediments.