TY - JOUR

T1 - Shotgun environmental DNA, pollen, and macrofossil analysis of lateglacial lake sediments from southern Sweden

AU - Parducci, Laura

AU - Alsos, Inger Greve

AU - Unneberg, Per

AU - Pedersen, Mikkel W.

AU - Han, Lu

AU - Lammers, Youri

AU - Salonen, J. Sakari

AU - Väliranta, Minna M.

AU - Slotte, Tanja

AU - Wohlfarth, Barbara

PY - 2019

Y1 - 2019

N2 - The lake sediments of Hässeldala Port in south-east Sweden provide an archive of local and regional environmental conditions ~14.5-9.5 ka BP (thousand years before present) and allow testing DNA sequencing techniques to reconstruct past vegetation changes. We combined shotgun sequencing with plant micro- and macrofossil analyses to investigate sediments dating to the Allerød (14.1-12.7 ka BP), Younger Dryas (12.7-11.7 ka BP), and Preboreal (<11.7 ka BP). Number of reads and taxa were not associated with sample age or organic content. This suggests that, beyond the initial rapid degradation, DNA is still present. The proportion of recovered plant DNA was low, but allowed identifying an important number of plant taxa, thus adding valid information on the composition of the local vegetation. Importantly, DNA provides a stronger signal of plant community changes than plant micro- and plant macrofossil analyses alone, since a larger number of new taxa were recorded in Younger Dryas samples. A comparison between the three proxies highlights differences and similarities and supports earlier findings that plants growing close to or within a lake are recorded by DNA. Plant macrofossil remains moreover show that tree birch was present close to the ancient lake since the Allerød; together with the DNA results, this indicates that boreal to subarctic climatic conditions also prevailed during the cold Younger Dryas interval. Increasing DNA reference libraries and enrichment strategies prior to sequencing are necessary to improve the potential and accuracy of plant identification using the shotgun metagenomic approach.

AB - The lake sediments of Hässeldala Port in south-east Sweden provide an archive of local and regional environmental conditions ~14.5-9.5 ka BP (thousand years before present) and allow testing DNA sequencing techniques to reconstruct past vegetation changes. We combined shotgun sequencing with plant micro- and macrofossil analyses to investigate sediments dating to the Allerød (14.1-12.7 ka BP), Younger Dryas (12.7-11.7 ka BP), and Preboreal (<11.7 ka BP). Number of reads and taxa were not associated with sample age or organic content. This suggests that, beyond the initial rapid degradation, DNA is still present. The proportion of recovered plant DNA was low, but allowed identifying an important number of plant taxa, thus adding valid information on the composition of the local vegetation. Importantly, DNA provides a stronger signal of plant community changes than plant micro- and plant macrofossil analyses alone, since a larger number of new taxa were recorded in Younger Dryas samples. A comparison between the three proxies highlights differences and similarities and supports earlier findings that plants growing close to or within a lake are recorded by DNA. Plant macrofossil remains moreover show that tree birch was present close to the ancient lake since the Allerød; together with the DNA results, this indicates that boreal to subarctic climatic conditions also prevailed during the cold Younger Dryas interval. Increasing DNA reference libraries and enrichment strategies prior to sequencing are necessary to improve the potential and accuracy of plant identification using the shotgun metagenomic approach.

KW - Ancient DNA

KW - Environmental DNA

KW - Lake sediments

KW - Macrofossils remains

KW - Pollen

KW - Shotgun sequencing (metagenomics)

U2 - 10.3389/fevo.2019.00189

DO - 10.3389/fevo.2019.00189

M3 - Journal article

AN - SCOPUS:85068599790

VL - 7

JO - Frontiers in Ecology and Evolution

JF - Frontiers in Ecology and Evolution

SN - 2296-701X

IS - JUN

M1 - 189

ER -