Ancient DNA complements microfossil record in deep-sea subsurface sediments
Ancient DNA complements microfossil record in deep-sea subsurface sediments
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DOI：
10.1098/rsbl.2013.0283
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发表时间：
2013-08-23
期刊：
影响因子：
3.3
通讯作者：
Pawlowski, Jan
中科院分区：
文献类型：
--
作者：
Lejzerowicz, Franck;Esling, Philippe;Pawlowski, Jan
深海地下沉积物是海洋生物多样性最重要的档案。迄今为止，这些档案的研究主要利用微化石记录，而忽略了深海海底积累的大量DNA。获取保存在核心下的古代 DNA (aDNA) 分子将为了解海洋生物多样性的历史提供独特的见解，包括化石和非化石类群。在这里，我们在南大西洋深海深处、距今长达 32500 年的沉积层中收集的四个岩心中恢复了真核起源的 DNA。我们的研究重点是有孔虫和放射虫，这是海洋微化石的两大类，也包含多种非化石类群。我们利用微古生物学和环境 DNA 测序方法描述了它们在岩心沉积层中的组合。从沉积 DNA 提取物中回收的有孔虫和放射虫小亚基 rRNA 基因的短片段提供了真核 aDNA 保存在末次盛冰期深海沉积物中的证据。大多数aDNA 都属于非化石类群，这些类群在现代环境的分子研究中也占主导地位。我们的研究揭示了aDNA在更好地记录过去海洋生态系统演化方面的潜力，并为深海古基因组学的发展开辟了新视野。
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.