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Genetic data from algae sedimentary DNA reflect the influence of environment over geography.

Stoof-Leichsenring KR, Herzschuh U, Pestryakova LA, Klemm J, Epp LS, Tiedemann R - Sci Rep (2015)

Bottom Line: Here, we investigate the relatedness of diatom lineages in Siberian lakes along environmental gradients (i.e. across treeline transects), over geographic distance and through time (i.e. the last 7000 years) using modern and ancient sedimentary DNA.Thus our study reveals that environmental conditions rather than geographic distance is reflected by diatom-relatedness patterns in space and time.We tentatively speculate that the detected relatedness pattern in Staurosira across the treeline could be a result of adaptation to diverse environmental conditions across the arctic boreal treeline, however, a geographically-driven divergence and subsequent repopulation of ecologically different habitats might also be a potential explanation for the observed pattern.

View Article: PubMed Central - PubMed

Affiliation: Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research, Telegrafenberg A43, 14473 Potsdam, Germany.

ABSTRACT
Genetic investigations on eukaryotic plankton confirmed the existence of modern biogeographic patterns, but analyses of palaeoecological data exploring the temporal variability of these patterns have rarely been presented. Ancient sedimentary DNA proved suitable for investigations of past assemblage turnover in the course of environmental change, but genetic relatedness of the identified lineages has not yet been undertaken. Here, we investigate the relatedness of diatom lineages in Siberian lakes along environmental gradients (i.e. across treeline transects), over geographic distance and through time (i.e. the last 7000 years) using modern and ancient sedimentary DNA. Our results indicate that closely-related Staurosira lineages occur in similar environments and less-related lineages in dissimilar environments, in our case different vegetation and co-varying climatic and limnic variables across treeline transects. Thus our study reveals that environmental conditions rather than geographic distance is reflected by diatom-relatedness patterns in space and time. We tentatively speculate that the detected relatedness pattern in Staurosira across the treeline could be a result of adaptation to diverse environmental conditions across the arctic boreal treeline, however, a geographically-driven divergence and subsequent repopulation of ecologically different habitats might also be a potential explanation for the observed pattern.

No MeSH data available.


Related in: MedlinePlus

Down-core variations (11-CH-12A): Calibrated 14C ages, core depth in cm, relative frequencies of the rbcl_c67 lineages (black arrows indicate the genetically analysed core samples) and Larix pollen percentage (data square-root transformed) of all terrestrial pollen grains.Lineages are grouped according Larix pollen affinity.
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f4: Down-core variations (11-CH-12A): Calibrated 14C ages, core depth in cm, relative frequencies of the rbcl_c67 lineages (black arrows indicate the genetically analysed core samples) and Larix pollen percentage (data square-root transformed) of all terrestrial pollen grains.Lineages are grouped according Larix pollen affinity.

Mentions: We defined the evolutionary relatedness between the lineages using patristic distances and used dbRDA to test for a correlation between lineages’ evolutionary relatedness and vegetation, and similarly with geography. Both datasets reveal a significant correlation with vegetation, but no (or only very weak) correlation with geography (Table 2). Accordingly, our results suggest that environmental variables, such as vegetation, rather than geographic distance, mainly impact the spatial genetic structure in our dataset. A comparison of spatial and temporal data of rbcL_67 lineages identified in modern and past sediments gave additional support for this assumption. Seven (a67/c67_01 to a67/c67_07) lineages were retrieved from both datasets, seven (a67_08 to a67_14) were detected only in modern sediments and five lineages (c67_15 to c67_20) were obtained only from cored sediments. Lineages present in sediment slices with a high Larix pollen percentage (>5%, lower part of the core) are mostly identical or similar (only one to two nucleotide differences) to lineages found in modern forested lakes, e.g. a/c67_07, a/c67_04, a67_04 and c67_17, a67_03/10 and c67_20. Lineages mainly retrieved from modern tundra lakes (a67_08, a67_09) differed in only one to two nucleotides from c67_16, a lineage occurring only at a very low Larix pollen percentage in the sediment core (Fig. 3). Moreover, dbRDA results show significant correlations between the rbcl_c67 lineages’ evolutionary relatedness and Larix pollen in the sediment core. This indicates that more closely-related Staurosira lineages occur in periods with similar vegetation (Table 2 and Fig. 4).


Genetic data from algae sedimentary DNA reflect the influence of environment over geography.

Stoof-Leichsenring KR, Herzschuh U, Pestryakova LA, Klemm J, Epp LS, Tiedemann R - Sci Rep (2015)

Down-core variations (11-CH-12A): Calibrated 14C ages, core depth in cm, relative frequencies of the rbcl_c67 lineages (black arrows indicate the genetically analysed core samples) and Larix pollen percentage (data square-root transformed) of all terrestrial pollen grains.Lineages are grouped according Larix pollen affinity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542542&req=5

f4: Down-core variations (11-CH-12A): Calibrated 14C ages, core depth in cm, relative frequencies of the rbcl_c67 lineages (black arrows indicate the genetically analysed core samples) and Larix pollen percentage (data square-root transformed) of all terrestrial pollen grains.Lineages are grouped according Larix pollen affinity.
Mentions: We defined the evolutionary relatedness between the lineages using patristic distances and used dbRDA to test for a correlation between lineages’ evolutionary relatedness and vegetation, and similarly with geography. Both datasets reveal a significant correlation with vegetation, but no (or only very weak) correlation with geography (Table 2). Accordingly, our results suggest that environmental variables, such as vegetation, rather than geographic distance, mainly impact the spatial genetic structure in our dataset. A comparison of spatial and temporal data of rbcL_67 lineages identified in modern and past sediments gave additional support for this assumption. Seven (a67/c67_01 to a67/c67_07) lineages were retrieved from both datasets, seven (a67_08 to a67_14) were detected only in modern sediments and five lineages (c67_15 to c67_20) were obtained only from cored sediments. Lineages present in sediment slices with a high Larix pollen percentage (>5%, lower part of the core) are mostly identical or similar (only one to two nucleotide differences) to lineages found in modern forested lakes, e.g. a/c67_07, a/c67_04, a67_04 and c67_17, a67_03/10 and c67_20. Lineages mainly retrieved from modern tundra lakes (a67_08, a67_09) differed in only one to two nucleotides from c67_16, a lineage occurring only at a very low Larix pollen percentage in the sediment core (Fig. 3). Moreover, dbRDA results show significant correlations between the rbcl_c67 lineages’ evolutionary relatedness and Larix pollen in the sediment core. This indicates that more closely-related Staurosira lineages occur in periods with similar vegetation (Table 2 and Fig. 4).

Bottom Line: Here, we investigate the relatedness of diatom lineages in Siberian lakes along environmental gradients (i.e. across treeline transects), over geographic distance and through time (i.e. the last 7000 years) using modern and ancient sedimentary DNA.Thus our study reveals that environmental conditions rather than geographic distance is reflected by diatom-relatedness patterns in space and time.We tentatively speculate that the detected relatedness pattern in Staurosira across the treeline could be a result of adaptation to diverse environmental conditions across the arctic boreal treeline, however, a geographically-driven divergence and subsequent repopulation of ecologically different habitats might also be a potential explanation for the observed pattern.

View Article: PubMed Central - PubMed

Affiliation: Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research, Telegrafenberg A43, 14473 Potsdam, Germany.

ABSTRACT
Genetic investigations on eukaryotic plankton confirmed the existence of modern biogeographic patterns, but analyses of palaeoecological data exploring the temporal variability of these patterns have rarely been presented. Ancient sedimentary DNA proved suitable for investigations of past assemblage turnover in the course of environmental change, but genetic relatedness of the identified lineages has not yet been undertaken. Here, we investigate the relatedness of diatom lineages in Siberian lakes along environmental gradients (i.e. across treeline transects), over geographic distance and through time (i.e. the last 7000 years) using modern and ancient sedimentary DNA. Our results indicate that closely-related Staurosira lineages occur in similar environments and less-related lineages in dissimilar environments, in our case different vegetation and co-varying climatic and limnic variables across treeline transects. Thus our study reveals that environmental conditions rather than geographic distance is reflected by diatom-relatedness patterns in space and time. We tentatively speculate that the detected relatedness pattern in Staurosira across the treeline could be a result of adaptation to diverse environmental conditions across the arctic boreal treeline, however, a geographically-driven divergence and subsequent repopulation of ecologically different habitats might also be a potential explanation for the observed pattern.

No MeSH data available.


Related in: MedlinePlus