Ancient plant DNA in lake sediments

ContentsSummary 924 I. Introduction 925 II. Environmental and temporal limits for survival of aDNA 925 III. Lake sediments 927 IV. Perspective for plant aDNA research 929 V. Perspective for plant aDNA research 930 VI. Pollen DNA 930 VII. Sedimentary aDNA 931 VIII. Recent key findings and future methods using HTS techniques 933 IX. Challenges when studying aDNA from lake sediments 935 X. Bioinformatic processing 936 XI. Conclusions and directions for future research 938Acknowledgements 938References 938Summary Recent advances in sequencing technologies now permit the analyses of plant DNA from fossil samples (ancient plant DNA , plant aDNA ), and thus enable the molecular reconstruction of palaeofloras. Hitherto, ancient frozen soils have proved excellent in preserving DNA molecules, and have thus been the most commonly used source of plant aDNA . However, DNA from soil mainly represents taxa growing a few metres from the sampling point. Lakes have larger catchment areas and recent studies have suggested that plant aDNA from lake sediments is a more powerful tool for palaeofloristic reconstruction. Furthermore, lakes can be found globally in nearly all environments, and are therefore not limited to perennially frozen areas. Here, we review the latest approaches and methods for the study of plant aDNA from lake sediments and discuss the progress made up to the present. We argue that aDNA analyses add new and additional perspectives for the study of ancient plant populations and, in time, will provide higher taxonomic resolution and more precise estimation of abundance. Despite this, key questions and challenges remain for such plant aDNA studies. Finally, we provide guidelines on technical issues, including lake selection, and we suggest directions for future research on plant aDNA studies in lake sediments.