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Anne K. Brysting

Bio: Anne K. Brysting is an academic researcher from University of Oslo. The author has contributed to research in topics: Population & Arctic vegetation. The author has an hindex of 30, co-authored 60 publications receiving 4446 citations. Previous affiliations of Anne K. Brysting include American Museum of Natural History & University of Gothenburg.


Papers
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Journal ArticleDOI
TL;DR: Polyploidy can be an important factor in species invasion success through a combination of 'pre-adaptation', whereby polyploid lineages are predisposed to conditions in the new range and, therefore, have higher survival rates and fitness in the earliest establishment phase.

653 citations

Journal ArticleDOI
TL;DR: It is concluded that the evolutionary success of polyploids in the Arctic may be based on their fixed-heterozygous genomes, which buffer against inbreeding and genetic drift through periods of dramatic climate change.
Abstract: The Arctic is an excellent model system for the study of polyploidy It is one the Earth's most polyploid-rich areas, in particular of high-level and recently evolved polyploids Here we re-address previous hypotheses on arctic polyploidy based on a new analysis of the circumarctic flora, and review recent molecular, cytological and reproductive studies The frequency and level of polyploidy strongly increase northwards within the Arctic We found no clear-cut association between polyploidy and the degree of glaciation for the arctic flora as a whole, which contains many widespread species However, for ‘arctic specialist’ taxa with restricted distributions, the frequency of diploids is much higher in the Beringian area, which remained largely unglaciated during the last ice age, than in the heavily glaciated Atlantic area This result supports the hypothesis that polyploids are more successful than diploids in colonizing after deglaciation There is abundant molecular evidence for recurrent formation of arctic polyploids at different scales in time and space Examples are given of low-level polyploids formed after the last glaciation and of repeated and successively more high-level polyploidizations throughout the Quaternary Recurrent polyploid origins, followed by interbreeding within and across ploidal levels, provide a major explanation for the taxonomic complexity of the arctic flora In the well-studied, recently deglaciated archipelago of Svalbard, most species are mainly self-fertilizing or clonal All Svalbard polyploids examined so far are genetic allopolyploids with fixed heterozygosity at isozyme loci The level of heterozygosity in 65 taxa increases dramatically from diploids to high-level polyploids In the circumarctic area, there is evidence for numerous recently evolved sibling species within diploid taxonomic species Rapid evolution of crossing barriers at the diploid level promotes further diversification after expansion from different refugia, and may provide new raw materials for allopolyploid formation We conclude that the evolutionary success of polyploids in the Arctic may be based on their fixed-heterozygous genomes, which buffer against inbreeding and genetic drift through periods of dramatic climate change © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 82, 521–536

527 citations

01 Jan 2012
TL;DR: In this article, the authors synthesize current knowledge on the importance of polyploidy for the invasion (i.e., spread) of introduced plants and provide an overview of ploidal levels in selected invasive alien plants and explain how ploidy might have contributed to their success.
Abstract: BACKGROUND Biological invasions are a major ecological and socio-economic problem in many parts of the world. Despite an explosion of research in recent decades, much remains to be understood about why some species become invasive whereas others do not. Recently, polyploidy (whole genome duplication) has been proposed as an important determinant of invasiveness in plants. Genome duplication has played a major role in plant evolution and can drastically alter a plant's genetic make-up, morphology, physiology and ecology within only one or a few generations. This may allow some polyploids to succeed in strongly fluctuating environments and/or effectively colonize new habitats and, thus, increase their potential to be invasive. SCOPE We synthesize current knowledge on the importance of polyploidy for the invasion (i.e. spread) of introduced plants. We first aim to elucidate general mechanisms that are involved in the success of polyploid plants and translate this to that of plant invaders. Secondly, we provide an overview of ploidal levels in selected invasive alien plants and explain how ploidy might have contributed to their success. CONCLUSIONS Polyploidy can be an important factor in species invasion success through a combination of (1) 'pre-adaptation', whereby polyploid lineages are predisposed to conditions in the new range and, therefore, have higher survival rates and fitness in the earliest establishment phase; and (2) the possibility for subsequent adaptation due to a larger genetic diversity that may assist the 'evolution of invasiveness'. Alternatively, polyploidization may play an important role by (3) restoring sexual reproduction following hybridization or, conversely, (4) asexual reproduction in the absence of suitable mates. We, therefore, encourage invasion biologists to incorporate assessments of ploidy in their studies of invasive alien species.

501 citations

Journal ArticleDOI
06 Feb 2014-Nature
TL;DR: The authors' analyses indicate that both graminoids and forbs would have featured in megafaunal diets, and question the predominance of a Late Quaternary graminoid-dominated Arctic mammoth steppe.
Abstract: Although it is generally agreed that the Arctic flora is among the youngest and least diverse on Earth, the processes that shaped it are poorly understood. Here we present 50 thousand years (kyr) of Arctic vegetation history, derived from the first large-scale ancient DNA metabarcoding study of circumpolar plant diversity. For this interval we also explore nematode diversity as a proxy for modelling vegetation cover and soil quality, and diets of herbivorous megafaunal mammals, many of which became extinct around 10 kyr bp (before present). For much of the period investigated, Arctic vegetation consisted of dry steppe-tundra dominated by forbs (non-graminoid herbaceous vascular plants). During the Last Glacial Maximum (25–15 kyr bp), diversity declined markedly, although forbs remained dominant. Much changed after 10 kyr bp, with the appearance of moist tundra dominated by woody plants and graminoids. Our analyses indicate that both graminoids and forbs would have featured in megafaunal diets. As such, our findings question the predominance of a Late Quaternary graminoid-dominated Arctic mammoth steppe.

460 citations

Journal ArticleDOI
TL;DR: Novel (high-throughput pyrosequencing) DNA barcoding technology for plant mixture with traditional microhistological method is compared, giving a detailed and relatively unbiased picture of food utilization of herbivores.
Abstract: Background: In order to understand the role of herbivores in trophic webs, it is essential to know what they feed on. Diet analysis is, however, a challenge in many small herbivores with a secretive life style. In this paper, we compare novel (high-throughput pyrosequencing) DNA barcoding technology for plant mixture with traditional microhistological method. We analysed stomach contents of two ecologically important subarctic vole species, Microtus oeconomus and Myodes rufocanus, with the two methods. DNA barcoding was conducted using the P6-loop of the chloroplast trnL (UAA) intron. Results: Although the identified plant taxa in the diets matched relatively well between the two methods, DNA barcoding gave by far taxonomically more detailed results. Quantitative comparison of results was difficult, mainly due to low taxonomic resolution of the microhistological method, which also in part explained discrepancies between the methods. Other discrepancies were likely due to biases mostly in the microhistological analysis. Conclusion: We conclude that DNA barcoding opens up for new possibilities in the study of plant-herbivore interactions, giving a detailed and relatively unbiased picture of food utilization of herbivores.

286 citations


Cited by
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01 Jun 2012
TL;DR: SPAdes as mentioned in this paper is a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler and on popular assemblers Velvet and SoapDeNovo (for multicell data).
Abstract: The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.

10,124 citations

01 Jan 2016
TL;DR: The modern applied statistics with s is universally compatible with any devices to read, and is available in the digital library an online access to it is set as public so you can download it instantly.
Abstract: Thank you very much for downloading modern applied statistics with s. As you may know, people have search hundreds times for their favorite readings like this modern applied statistics with s, but end up in harmful downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some harmful virus inside their laptop. modern applied statistics with s is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library saves in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the modern applied statistics with s is universally compatible with any devices to read.

5,249 citations

Journal ArticleDOI

3,734 citations

Journal ArticleDOI
TL;DR: The advantages and challenges of polyploidy, and its evolutionary potential, are considered.
Abstract: Polyploids — organisms that have multiple sets of chromosomes — are common in certain plant and animal taxa, and can be surprisingly stable. The evidence that has emerged from genome analyses also indicates that many other eukaryotic genomes have a polyploid ancestry, suggesting that both humans and most other eukaryotes have either benefited from or endured polyploidy. Studies of polyploids soon after their formation have revealed genetic and epigenetic interactions between redundant genes. These interactions can be related to the phenotypes and evolutionary fates of polyploids. Here, I consider the advantages and challenges of polyploidy, and its evolutionary potential.

1,882 citations

Journal ArticleDOI
TL;DR: A perspective on the context and evolutionary significance of hybridization during speciation is offered, highlighting issues of current interest and debate and suggesting that the Dobzhansky–Muller model of hybrid incompatibilities requires a broader interpretation.
Abstract: Hybridization has many and varied impacts on the process of speciation. Hybridization may slow or reverse differentiation by allowing gene flow and recombination. It may accelerate speciation via adaptive introgression or cause near-instantaneous speciation by allopolyploidization. It may have multiple effects at different stages and in different spatial contexts within a single speciation event. We offer a perspective on the context and evolutionary significance of hybridization during speciation, highlighting issues of current interest and debate. In secondary contact zones, it is uncertain if barriers to gene flow will be strengthened or broken down due to recombination and gene flow. Theory and empirical evidence suggest the latter is more likely, except within and around strongly selected genomic regions. Hybridization may contribute to speciation through the formation of new hybrid taxa, whereas introgression of a few loci may promote adaptive divergence and so facilitate speciation. Gene regulatory networks, epigenetic effects and the evolution of selfish genetic material in the genome suggest that the Dobzhansky-Muller model of hybrid incompatibilities requires a broader interpretation. Finally, although the incidence of reinforcement remains uncertain, this and other interactions in areas of sympatry may have knock-on effects on speciation both within and outside regions of hybridization.

1,715 citations