Ancient DNA

Abstract

DNA-sequence information can, in principle, be retrieved from archaeological and palaeontological remains that are less than ∼100,000 years old. In most circumstances, only multicopy DNA, such as mitochondrial DNA (mtDNA) and chloroplast DNA, can be retrieved. Extensive control experiments are necessary to ensure that results are not caused by contamination with modern or recent DNA. Human remains are particularly difficult to work with because human DNA is almost ubiquitously present on old specimens and laboratory equipment. Owing to the technical difficulties, not all published results in the field are reliable. Using the techniques for ancient DNA retrieval, zoological and botanical museum collections from the past two centuries are important repositories of molecular genetic information. The biological relationships and history of many Ice Age animals have been clarified using ancient DNA. The mtDNA of Neanderthals has been shown not to be present among contemporary humans. Coprolites represent a source of genetic information about animals and their diet that is often more reliable than bones from the same time period. Cold environments are particularly conducive to DNA preservation. Population studies of extinct animals, plants and Neanderthals are becoming possible.