From entities to interaction. Replacing pots and people with networks of transmission

Source at https://www.sgr.fi/en/items/show/675.The understanding of the relationship between language, ethnic groups, and material culture in prehistory is still very limited, even within highly competent academic communities. To researchers without archaeological training it may be easy to make a direct association between archaeological cultures, distribution of signifi cant artefact types, and ethnic groups, especially as such explicit links are occasionally made also by archaeologists (e.g. Carpelan 2006). While there is undoubtedly some association between material culture and ethnicity (Damm 2010), and by inference perhaps also language, this is not straightforward, and is in many respects still poorly understood

Interaction Within and Between Collectives: Networking in Northern Fennoscandia

Source at https://www.sgr.fi/en/items/show/675.The project Early Networking in Northern Fennoscandia is concerned with investigating interaction at the regional and interregional levels. Through a number of separate case studies we look into the substance of the interaction, evaluate its extent and diversity, background and organization, and its wider effects. In my case study I approach interregional interaction by looking at networks and collective identities. The following focuses on the importance of collectives in interaction

A Neolithic Corridor between East and West.

Source at http://www.sarks.fi/masf/masf_10/masf_10.html.The discovery of an amber bead and an unusual type of slate knife at a site near Tromsø, Norway instigated reflection upon inter-regional mobility and possible travel routes in northern Fennoscandia. In combination with finds near Kilpisjärvi, Finland, these early Neolithic objects found far from their main distribution area allow us to suggest that the Torne River and its connected waterways provided a corridor for contact between the Atlantic coast and the Bothnian coast

Introduction

Source at https://www.sgr.fi/en/items/show/675.This volume is a collection of articles based on papers that were presented at the conference Networks, Interaction and Emerging Identities in Fennoscandia and Beyond, 13–16 October 2009. The conference was held at the University of Tromsø in Norway, and hosted by its Department of Archaeology and Social Anthropology at the Faculty of Humanities, Social Sciences and Education. The University of Tromsø was the obvious choice of venue due to its explicit research emphasis on northern regions and indigenous identities, as well as its location in an area where hunter-fisher-gatherer populations persisted well into the second millenium AD

The evolutionary history of the Arabidopsis lyrata complex: a hybrid in the amphi-Beringian area closes a large distribution gap and builds up a genetic barrier

<p>Abstract</p> <p>Background</p> <p>The genomes of higher plants are, on the majority, polyploid, and hybridisation is more frequent in plants than in animals. Both polyploidisation and hybridisation contribute to increased variability within species, and may transfer adaptations between species in a changing environment. Studying these aspects of evolution within a diversified species complex could help to clarify overall spatial and temporal patterns of plant speciation. The <it>Arabidopsis lyrata </it>complex, which is closely related to the model plant <it>Arabidopsis thaliana</it>, is a perennial, outcrossing, herbaceous species complex with a circumpolar distribution in the Northern Hemisphere as well as a disjunct Central European distribution in relictual habitats. This species complex comprises three species and four subspecies, mainly diploids but also several tetraploids, including one natural hybrid. The complex is ecologically, but not fully geographically, separated from members of the closely related species complex of <it>Arabidopsis halleri</it>, and the evolutionary histories of both species compexes have largely been influenced by Pleistocene climate oscillations.</p> <p>Results</p> <p>Using DNA sequence data from the nuclear encoded cytosolic phosphoglucoisomerase and Internal Transcribed Spacers 1 and 2 of the ribosomal DNA, as well as the <it>trn</it>L/F region from the chloroplast genome, we unravelled the phylogeography of the various taxonomic units of the <it>A. lyrata </it>complex. We demonstrate the existence of two major gene pools in Central Europe and Northern America. These two major gene pools are constructed from different taxonomic units. We also confirmed that <it>A. kamchatica </it>is the allotetraploid hybrid between <it>A. lyrata </it>and <it>A. halleri</it>, occupying the amphi-Beringian area in Eastern Asia and Northern America. This species closes the large distribution gap of the various other <it>A. lyrata </it>segregates. Furthermore, we revealed a threefold independent allopolyploid origin of this hybrid species in Japan, China, and Kamchatka.</p> <p>Conclusions</p> <p>Unglaciated parts of the Eastern Austrian Alps and arctic Eurasia, including Beringia, served as major glacial refugia of the Eurasian <it>A. lyrata </it>lineage, whereas <it>A. halleri </it>and its various subspecies probably survived in refuges in Central Europe and Eastern Asia with a large distribution gap in between. The North American <it>A. lyrata </it>lineage probably survived the glaciation in the southeast of North America. The dramatic climatic changes during glaciation and deglaciation cycles promoted not only secondary contact and formation of the allopolyploid hybrid <it>A. kamchatica</it>, but also provided the environment that allowed this species to fill a large geographic gap separating the two genetically different <it>A. lyrata </it>lineages from Eurasia and North America. With our example focusing on the evolutionary history of the <it>A. lyrata </it>species complex, we add substantial information to a broad evolutionary framework for future investigations within this emerging model system in molecular and evolutionary biology.</p

Interspecific and interploidal gene flow in Central European Arabidopsis (Brassicaceae)

Background Effects of polyploidisation on gene flow between natural populations are little known. Central European diploid and tetraploid populations of Arabidopsis arenosa and A. lyrata are here used to study interspecific and interploidal gene flow, using a combination of nuclear and plastid markers. Results Ploidal levels were confirmed by flow cytometry. Network analyses clearly separated diploids according to species. Tetraploids and diploids were highly intermingled within species, and some tetraploids intermingled with the other species, as well. Isolation with migration analyses suggested interspecific introgression from tetraploid A. arenosa to tetraploid A. lyrata and vice versa, and some interploidal gene flow, which was unidirectional from diploid to tetraploid in A. arenosa and bidirectional in A. lyrata. Conclusions Interspecific genetic isolation at diploid level combined with introgression at tetraploid level indicates that polyploidy may buffer against negative consequences of interspecific hybridisation. The role of introgression in polyploid systems may, however, differ between plant species, and even within the small genus Arabidopsis, we find very different evolutionary fates when it comes to introgression

Nuisance growth of Juncus bulbosus: the roles of genetics and environmental drivers tested in a large-scale survey

1. Invasive species can transform aquatic ecosystems, and the nuisance growth of the freshwater macrophyte Juncus bulbosus has become a problem in many lakes and rivers in northern Europe. It affects biodiversity strongly and conflicts with human uses, not least compromising the generation of hydroelectricity. The causes of the proliferation of these massive stands of J. bulbosus are not finally resolved, however. 2. In this study, a wide range of catchment, lake and sediment parameters (n = 34) were assessed for 139 lakes in Southern Norway, with the aim of explaining the presence or absence of J. bulbosus and to assess potential drivers behind its prolific growth. 3. Juncus bulbosus was more often present in lakes with lower pH and phosphate concentrations, and a higher element ratio of dissolved inorganic nitrogen (DIN) to total phosphorus (DIN : TotP). 4. Despite the many parameters measured across substantial environmental gradients, none explained nuisance growth. Genetic screening (amplified fragment length polymorphism fingerprinting) of plants from a subset of lakes and additional river sites also showed no genetic differences between the various growth forms. A macrophyte trophic index, however, suggested that the most problematic growth occurred in the most oligotrophic lakes. 5. The lack of consistent patterns may reflect either factors not assessed in our survey, or that the current extension of stands represents a gradual cumulative response over time, not characterised effectively in our snapshot survey. Nevertheless, we can now exclude some putative causes of nuisance growth, including in particular genetics and N‐deposition.acceptedVersio

What can cold-induced transcriptomes of Arctic Brassicaceae tell us about the evolution of cold tolerance?

publishedVersio

High diversity of root associated fungi in both alpine and arctic Dryas octopetala

<p>Abstract</p> <p>Background</p> <p><it>Dryas octopetala </it>is a widespread dwarf shrub in alpine and arctic regions that forms ectomycorrhizal (ECM) symbiotic relationships with fungi. In this study we investigated the fungal communities associated with roots of <it>D. octopetala </it>in alpine sites in Norway and in the High Arctic on Svalbard, where we aimed to reveal whether the fungal diversity and species composition varied across the Alpine and Arctic regions. The internal transcribed spacer (ITS) region of nuclear ribosomal DNA was used to identify the fungal communities from bulk root samples obtained from 24 plants.</p> <p>Results</p> <p>A total of 137 operational taxonomic units (OTUs) were detected (using 97% similarity cut off during sequence clustering) and well-known ECM genera such as <it>Cenococcum</it>, <it>Cortinarius, Hebeloma</it>, <it>Inocybe </it>and <it>Tomentella </it>occurred frequently. There was no decrease in fungal diversity with increasing latitude. The overall spatial heterogeneity was high, but a weak geographical structuring of the composition of OTUs in the root systems was observed. Calculated species accumulation curves did not level off.</p> <p>Conclusions</p> <p>This study indicates that the diversity of fungi associated with <it>D. octopetala </it>does not decrease in high latitude arctic regions, which contrasts observations made in a wide spectrum of other organism groups. A high degree of patchiness was observed across root systems, but the fungal communities were nevertheless weakly spatially structured. Non-asymptotical species accumulation curves and the occurrence of a high number of singletons indicated that only a small fraction of the fungal diversity was detected.</p