title: Ancient DNA complements microfossil record in deep-sea subsurface sediments.
abstract: Deep-sea subsurface sediments are the most important archives of marine biodiversity. Until now, these archives were studied mainly using the microfossil record, disregarding large amounts of DNA accumulated on the deep-sea floor. Accessing ancient DNA (aDNA) molecules preserved down-core would offer unique insights into the history of marine biodiversity, including both fossilized and non-fossilized taxa. Here, we recover aDNA of eukaryotic origin across four cores collected at abyssal depths in the South Atlantic, in up to 32.5 thousand-year-old sediment layers. Our study focuses on Foraminifera and Radiolaria, two major groups of marine microfossils also comprising diverse non-fossilized taxa. We describe their assemblages in down-core sediment layers applying both micropalaeontological and environmental DNA sequencing approaches. Short fragments of the foraminiferal and radiolarian small subunit rRNA gene recovered from sedimentary DNA extracts provide evidence that eukaryotic aDNA is preserved in deep-sea sediments encompassing the last glacial maximum. Most aDNA were assigned to non-fossilized taxa that also dominate in molecular studies of modern environments. Our study reveals the potential of aDNA to better document the evolution of past marine ecosystems and opens new horizons for the development of deep-sea palaeogenomics.
authors: Department of Genetics and Evolution, University of Geneva, Genève 4, Switzerland. franck.lejzerowicz@unige.ch
authors: Franck
authors: F
authors: Lejzerowicz
authors: Philippe
authors: P
authors: Esling
authors: Wojciech
authors: W
authors: Majewski
authors: Witold
authors: W
authors: Szczuciński
authors: Johan
authors: J
authors: Decelle
authors: Cyril
authors: C
authors: Obadia
authors: Pedro Martinez
authors: PM
authors: Arbizu
authors: Jan
authors: J
authors: Pawlowski
mesh_terms: D001267:Atlantic Ocean; D016054:DNA, Protozoan / Q000032:analysis*; D056908:Foraminifera / Q000145:classification / Q000235:genetics / Q000378:metabolism; D005580:Fossils; D019015:Geologic Sediments / Q000032:analysis*; D008969:Molecular Sequence Data; D056901:Rhizaria / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D016054:DNA, Protozoan
keywords: ancient DNA; deep-sea sediments; microfossils; next-generation sequencing; palaeogenomics
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