Variation in insect herbivory across an urbanization gradient: The role of abiotic factors and leaf secondary metabolites.

Urbanization impacts plant-herbivore interactions, which are crucial for ecosystem functions such as carbon sequestration and nutrient cycling. While some studies have reported reductions in insect herbivory in urban areas (relative to rural or natural forests), this trend is not consistent and the underlying causes for such variation remain unclear. We conducted a continental-scale study on insect herbivory along urbanization gradients for three European tree species: Quercus robur, Tilia cordata, and Fraxinus excelsior, and further investigated their biotic and abiotic correlates to get at mechanisms.

The chronology of the human colonization of the Canary Islands.

The human colonization of the Canary Islands represents the sole known expansion of Berber communities into the Atlantic Ocean and is an example of marine dispersal carried out by an African population. While this island colonization shows similarities to the populating of other islands across the world, several questions still need to be answered before this case can be included in wider debates regarding patterns of initial colonization and human settlement, human-environment interactions, and the emergence of island identities. Specifically, the chronology of the first human settlement of the Canary Islands remains disputed due to differing estimates of the timing of its first colonization.

Limited genetic changes observed during and conservation in Nordic populations of red clover ().

Introduction: and conservation are the two main approaches for preserving genetic diversity. The advantages and disadvantages of the two approaches have been discussed but their genetic effects have not been fully evaluated.

Methods: In this study we investigate the effects of the two conservation approaches on genetic diversity in red clover.

Protein content and HvNAM alleles in Nordic barley (Hordeum vulgare) during a century of breeding.

Background: Barley has been bred for more than a century in the Nordic countries, with dramatic improvements of yield traits. In this study we investigate if this has come at the cost of lower grain protein and micronutrient (iron, zinc) content, by analysing 80 accessions representing four different improvement stages. We further re-sequenced the two grain protein content associated genes HvNAM-1 and HvNAM-2 in full and performed expression analyses of the same genes to search for genetic associations with nutrient content.

An Evolutionary Approach to the History of Barley () Cultivation in the Canary Islands.

The Canary Islands are an archipelago that lies about 100 km west of North Africa. Barley () has been continuously cultivated since the colonization of the islands. To investigate the agricultural history of the islands, the DNA from multiple individuals of six extant landraces of barley was sequenced, and the resulting data were analyzed with ABC modeling.

SNP Markers and Evaluation of Duplicate Holdings of in Two European Genebanks.

Around the world, there are more than 1500 genebanks storing plant genetic resources to be used in breeding and research. Such resources are essential for future food security, but many genebanks experience backlogs in their conservation work, often combined with limited budgets. Therefore, avoiding duplicate holdings is on the agenda.

Population structure in landrace barley (Hordeum vulgare L.) during the late 19th century crop failures in Fennoscandia.

Agricultural disasters and the subsequent need for supply of relief seed can be expected to influence the genetic composition of crop plant populations. The consequences of disasters and seed relief have, however, rarely been studied since specimens sampled before the events are seldomly available. A series of crop failures struck northern Fennoscandia (Norway, Sweden and Finland) during the second half of the 19th century.

No genetic erosion after five generations for Impatiens glandulifera populations across the invaded range in Europe.

Background: The observation that many alien species become invasive despite low genetic diversity has long been considered the 'genetic paradox' in invasion biology. This paradox is often resolved through the temporal buildup genetic diversity through multiple introduction events. These temporal dynamics in genetic diversity are especially important for annual invasive plants that lack a persistent seed bank, for which population persistence is strongly dependent on consecutive seed 're-establishment' in each growing season.

Patterns of Exchange of Multiplying Onion ( L. Aggregatum-Group) in Fennoscandian Home Gardens.

Multiplying onion ( L. Aggregatum-Group), commonly known as shallot or potato onion, has a long tradition of cultivation in Fennoscandian home gardens. During the last decades, more than 80 accessions, maintained as vegetatively propagated clones, have been gathered from home gardens in all Fennoscandian countries.

Evolutionary history of the NAM-B1 gene in wild and domesticated tetraploid wheat.

Background: The NAM-B1 gene in wheat has for almost three decades been extensively studied and utilized in breeding programs because of its significant impact on grain protein and mineral content and pleiotropic effects on senescence rate and grain size. First detected in wild emmer wheat, the wild-type allele of the gene has been introgressed into durum and bread wheat. Later studies have, however, also found the presence of the wild-type allele in some domesticated subspecies.

Flowering time adaption in Swedish landrace pea (Pisum sativum L.).

Background: Cultivated crops have repeatedly faced new climatic conditions while spreading from their site of origin. In Sweden, at the northernmost fringe of Europe, extreme conditions with temperature-limited growth seasons and long days require specific adaptation. Pea (Pisum sativum L.

A domestication related mutation in the thyroid stimulating hormone receptor gene (TSHR) modulates photoperiodic response and reproduction in chickens.

The thyroid stimulating hormone receptor gene (TSHR) has been suggested to be a "domestication locus" in the chicken. A strong selective sweep over TSHR in domestic breeds together with significant effects of a mutation in the gene on several domestication related traits, indicate that the gene has been important for chicken domestication. TSHR plays a key role in the signal transduction of seasonal reproduction, which is characteristically less strict in domestic animals.

Geographical distribution of genetic diversity in Secale landrace and wild accessions.

Background: Rye, Secale cereale L., has historically been a crop of major importance and is still a key cereal in many parts of Europe. Single populations of cultivated rye have been shown to capture a large proportion of the genetic diversity present in the species, but the distribution of genetic diversity in subspecies and across geographical areas is largely unknown.

Strong Maternal Effects on Gene Expression in Arabidopsis lyrata Hybrids.

Hybridization between populations or species can have pronounced fitness consequences. Yet little is known about how hybridization affects gene regulation. Three main models have been put forward to explain gene expression patterns in hybrids: additive, dominance, or parental effects.

Low genetic diversity despite multiple introductions of the invasive plant species Impatiens glandulifera in Europe.

Background: Invasive species can be a major threat to native biodiversity and the number of invasive plant species is increasing across the globe. Population genetic studies of invasive species can provide key insights into their invasion history and ensuing evolution, but also for their control. Here we genetically characterise populations of Impatiens glandulifera, an invasive plant in Europe that can have a major impact on native plant communities.

Wheat in the Mediterranean revisited--tetraploid wheat landraces assessed with elite bread wheat Single Nucleotide Polymorphism markers.

Background: Single Nucleotide Polymorphism (SNP) panels recently developed for the assessment of genetic diversity in wheat are primarily based on elite varieties, mostly those of bread wheat. The usefulness of such SNP panels for studying wheat evolution and domestication has not yet been fully explored and ascertainment bias issues can potentially affect their applicability when studying landraces and tetraploid ancestors of bread wheat. We here evaluate whether population structure and evolutionary history can be assessed in tetraploid landrace wheats using SNP markers previously developed for the analysis of elite cultivars of hexaploid wheat.

Strong inbreeding depression in two Scandinavian populations of the self-incompatible perennial herb Arabidopsis lyrata.

Inbreeding depression is a key factor influencing mating system evolution in plants, but current understanding of its relationship with selfing rate is limited by a sampling bias with few estimates for self-incompatible species. We quantified inbreeding depression (δ) over two growing seasons in two populations of the self-incompatible perennial herb Arabidopsis lyrata ssp. petraea in Scandinavia.

Strong presence of the high grain protein content allele of NAM-B1 in Fennoscandian wheat.

Grain protein content in wheat has been shown to be affected by the NAM-B1 gene where the wildtype allele confers high levels of protein and micronutrients but can reduce yield. Two known non-functional alleles instead increase yield but lead to lower levels of protein and micronutrients. The wildtype allele in hexaploid bread wheat is so far mainly known from historical specimens and a few lines with an emmer wheat introgression.

Allelic variation at the Rht8 locus in a 19th century wheat collection.

Wheat breeding during the 20th century has put large efforts into reducing straw length and increasing harvest index. In the 1920s an allele of Rht8 with dwarfing effects, found in the Japanese cultivar "Akakomugi," was bred into European cultivars and subsequently spread over the world. Rht8 has not been cloned, but the microsatellite marker WMS261 has been shown to be closely linked to it and is commonly used for genotyping Rht8.

Nineteenth century seeds reveal the population genetics of landrace barley (Hordeum vulgare).

Barley (Hordeum vulgare) is a major crop, grown worldwide and in a wide range of climatic conditions. Despite its importance as a crop species, little is known about the population genetics of barley and the effects of bottlenecks, adaptation, and gene flow on genetic diversity within and between landrace populations. In areas with highly developed agriculture, such as Northern Europe, these types of genetic studies are hampered by lack of landraces preserved in situ or ex situ.

Population genomics of the inbred Scandinavian wolf.

The Scandinavian wolf population represents one of the genetically most well-characterized examples of a severely bottlenecked natural population (with only two founders), and of how the addition of new genetic material (one immigrant) can at least temporarily provide a 'genetic rescue'. However, inbreeding depression has been observed in this population and in the absence of additional immigrants, its long-term viability is questioned. To study the effects of inbreeding and selection on genomic diversity, we performed a genomic scan with approximately 250 microsatellite markers distributed across all autosomes and the X chromosome.

Comparative gene mapping in Arabidopsis lyrata chromosomes 6 and 7 and A. thaliana chromosome IV: evolutionary history, rearrangements and local recombination rates.

We have increased the density of genetic markers on the Arabidopsis lyrata chromosomes AL6 and AL7 corresponding to the A. thaliana chromosome IV, in order to determine chromosome rearrangements between these two species, and to compare recombination fractions across the same intervals. We confirm the two rearrangements previously inferred (a reciprocal translocation and a large inversion, which we infer to be pericentric).

Centromere locations and associated chromosome rearrangements in Arabidopsis lyrata and A. thaliana.

We analyzed linkage and chromosomal positions of genes in A. lyrata ssp. petraea that are located near the centromere (CEN) regions of A.

Linkage disequilibrium between incompatibility locus region genes in the plant Arabidopsis lyrata.

We have studied diversity in Arabidopsis lyrata of sequences orthologous to the ARK3 gene of A. thaliana. Our main goal was to test for recombination in the S-locus region.

A unique recent origin of the allotetraploid species Arabidopsis suecica: Evidence from nuclear DNA markers.

A coalescent-based method was used to investigate the origins of the allotetraploid Arabidopsis suecica, using 52 nuclear microsatellite loci typed in eight individuals of A. suecica and 14 individuals of its maternal parent Arabidopsis thaliana, and four short fragments of genomic DNA sequenced in a sample of four individuals of A. suecica and in both its parental species A.