Reconstructing past vegetation communities using ancient DNA from lake sediments

The field of ancient DNA has received much attention since the mid-1980s, when the first sequences of extinct species were obtained from museum and archaeological specimens. Early analyses focused on organellar DNA (mitochondrial in animals and chloroplast in plants) as these are present in multiple copies in the cells making isolation and analyses easier. Within the last decade, however, with considerable advances in high-throughput DNA sequencing technology and bioinformatics, it has become possible to analyse the more informative nuclear genome of a larger number of ancient samples and from a larger variety of substrates and environments. Here, we present recent progress made to reconstruct ancient vegetation communities from lake sediments and review recent key findings in the field. We synthesize and discuss the sources of plant DNA in sediment, the issues relating to DNA preservation after deposition, the criteria required for authentication and the technical advances recently made in the field for the analyses and the taxonomic identification of plant ancient DNA sequences obtained from these complex substrates. Together, these advances mean that we are on the way to an explosion of new information for the investigation of ancient plant environments.