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PREMISE Understanding the adaptive capacities of species over long timescales lies in examining the revived recent and millennia old resting spores buried in sediments. We show for the first time the revival, viability and germination rate of resting spores of the diatom Chaetoceros deposited in sub-seafloor sediments from three ages (recent: 0-80 years; ancient: ~1250 (Medieval Climate Anomaly) and ~6600 (Holocene Thermal Maximum) calendar year before present. METHODS Recent and ancient Chaetoceros spores were revived to examine their viability and germination rate. Light and scanning electron microscopy and Sanger sequencing was done to identify the species. KEY RESULTS We show that ~6600 cal. year BP old Chaetoceros resting spores are still viable and the vegetative reproduction in recent and ancient resting spores vary. The time taken to germinate is three hours to 2-3 days in both recent and ancient spores, but the germination rate of the spores decreased with increasing age. The germination rate of the recent spores was ~41% while that of the ancient spores were ~31% and ~12% for the ~1250 and ~6600 cal. year BP old resting spores. Based on the morphology of the germinated vegetative cells we identified the species as Chaetoceros muelleri var. subsalsum. Sanger sequences of nuclear and chloroplast markers identified the species as Chaetoceros muelleri. CONCLUSIONS We identify a unique model system, Chaetoceros muelleri var. subsalsum and show that recent and ancient resting spores of the species buried in sediments in the Baltic Sea can be revived and used for long-term evolutionary studies. This article is protected by copyright. All rights reserved.

We have reviewed information on early-, late- and limit-value decomposition stages for litter of Norway spruce (Picea abies) and Scots pine (Pinus silvestris). This synthesis covers c 16 studies/papers made along a climatic gradient; range in mean annual temperature (MAT) from −1 to +7 °C and mean annual precipitation (MAP) from 425 to 1070 mm. Scots pine has an early stage dominated by carbohydrate decomposition and a late stage dominated by decomposition of lignin; Norway spruce has just one stage dominated by lignin decomposition. We used data for annual mass loss to identify rate-regulating factors in both stages; climate data, namely, MAT and MAP, as well as substrate properties, namely, nitrogen (N), acid unhydrolyzable residue (AUR), manganese (Mn). Early-stage decomposition for Scots pine litter was dominated positively by MAT; the late stage was dominated negatively by MAT, N, and AUR, changing with decomposition stage; there was no effect of Mn. Norway spruce litter had no early stage; decomposition in the lignin-dominated stage was mainly negative to MAP, a negative relationship to AUR and non-significant relationships to N and MAT. Mn had a positive relationship. Limit values for decomposition, namely, the accumulated mass loss at which decomposition is calculated to be zero, were related positively to Mn and AUR for Scots pine litter and negatively to AUR for Norway spruce litter. With different sets of rate-regulating factors as well as different compounds/elements related to the limit values, the decomposition patterns or pathways are different.

We synthesized available data for magnesium (Mg) dynamics in newly shed and decomposing foliar litter of mainly pine (Pinus) species, Norway spruce (Picea abies), and birch (Betula) species. Using original, measured data from 40 stands organized in climatic gradients we intended to determine patterns of Mg concentration and net release vs accumulated mass loss of the litter. This synthesis is likely the first synthesis of Mg dynamics in decomposing litter. In paired stands, litter of both Norway spruce and lodgepole pine (Pinus contorta) had higher Mg concentrations than Scots pine (Pinus silvestris), with concentrations in Norway spruce litter even twice as high. In decomposing litter, Mg concentrations followed a quadratic (X2-X) function vs accumulated mass loss and consequently had minima, different for Norway spruce and Scots pine litter. Out of 68 decomposition studies 53 gave minimum concentration. The Mg minimum concentration during decomposition was positively related to initial Mg concentration for Scots pine and Scots pine plus lodgepole pine but not for Norway spruce. The increase in concentration suggests that after the minimum Mg was temporarily limiting. For Norway spruce litter there was a relationship between minimum concentration of Mg and the limit value. There was no such relationship for Scots pine and not for the combined pine data. Magnesium net release started directly after the incubation and was linear to accumulated mass loss of litter, giving a slope coefficient (release rate) for each study. The net release rate was linear to initial Mg concentration and all studies combined gave a negative linear relationship.

A sediment record from the western Gotland Basin, northwestern Baltic Proper, covering the last 1200 years, was investigated for past changes in climate and the environment using diatoms as a proxy. The aim is to compare the environmental conditions reconstructed during Medieval times with settings occurring the last century under influence of environmental stressors like eutrophication and climate change. The study core records more marine conditions in the western Gotland Basin surface waters during the Medieval Climate Anomaly (MCA; 950–1250C.E.), with a salinity of at least 8 psu compared to the present 6.5 psu. The higher salinity together with a strong summer-autumn stratification caused by warmer climate resulted in extensive long-lasting diatom blooms of Pseudosolenia calcar-avis, effectively enhancing the vertical export of organic carbon to the sediment and contributing to benthic hypoxia. Accordingly, our data support that a warm and dry climate induced the extensive hypoxic areas in the open Baltic Sea during the MCA. During the Little ice Age (LIA; 1400–1700C.E.), the study core records oxic bottom water conditions, decreasing salinity and less primary production. This was succeeded during the 20th century, about 1940, by environmental changes caused by human-induced eutrophication. Impact of climate change is visible in the diatom composition data starting about 1975C.E. and becoming more pronounced 2000C.E., visible as an increase of taxa that thrived in stratified waters during autumn blooms typically due to climate warming.

Microscopic marine planktons have played a major role in the Earth’s ecosystem and accounts for half the globe’s primary production. Predicting the fate of marine planktons is imperative to understanding how ocean life will change in future centuries and how organisms have adapted to changes in the past over long timescales (over thousands of years). Studies of revived resting spores of marine diatoms will serve as excellent proxies of environmental change in marine environments. Thus far, only about a century old marine diatom resting spores could be revived. This severely limited the use of diatom resting spores to investigate the effects of environmental perturbations over longer time scales. Here, we, for the first time report revival of thousands of years old resting spores from the deposits of ancient diatoms (Chaetoceros) in sub-seafloor sediments using a revival protocol that involved recreating the ancient environmental conditions (salinity, temperature and light). Our revived diatom resting spores samples range from recent (0-80 years) to ∼7200 years old. Importantly, we also extracted the DNA from the ancient resting spores ofChaetocerosspecies from the Baltic Sea. Our findings will enable us to compare DNA sequence data obtained from these natural archives of resurrected organisms and provide predictive models to forecast evolutionary responses of natural populations to environmental changes resulting from natural and anthropogenic stressors, including climate changeSignificance StatementOur results address the important topic of adaptive evolution in marine species due to climate and environmental change induced due to anthropogenic perturbations. We present a new model systemChaetoceros muelleriwhich will help us address important evolutionary and long-term adaptation questions across evolutionary timescales. Our study reports (1) the revival of recent (0-80 years) to ancient (7200 years old) resting spores ofChaetoceros(2) the extraction of DNA and amplification of chloroplast and ribosomal genes from recent and ancient (∼1300 years old) resting spores ofChaetoceros(3) Radiocarbon dating to determine age of sediments (4) Identification of species by reviving the resting spores (5) Baltic sea an excellent ecosystem to study long-term effects of environment on species adaptation

Human-derived environmental pollutants and nutrients that reach the aquatic environment through sewage effluents, agricultural and industrial processes are constantly contributing to environmental changes that serve as drivers for adaptive responses and evolutionary changes in many taxa. In this study, we examined how two types of point sources of aquatic environmental pollution, harbors and sewage treatment plants, affect gene diversity and genetic differentiation in the blue mussel in the Baltic Sea area and off the Swedish west coast (Skagerrak). Reference sites (REF) were geographically paired with sites from sewage treatments plant (STP) and harbors (HAR) with a nested sampling scheme, and genetic differentiation was evaluated using a high-resolution marker amplified fragment length polymorphism (AFLP). This study showed that genetic composition in the Baltic Sea blue mussel was associated with exposure to sewage treatment plant effluents. In addition, mussel populations from harbors were genetically divergent, in contrast to the sewage treatment plant populations, suggesting that there is an effect of pollution from harbors but that the direction is divergent and site specific, while the pollution effect from sewage treatment plants on the genetic composition of blue mussel populations acts in the same direction in the investigated sites.

We combine historical maps and satellite derived data to reconstruct the development of a Swedish boreal landscape over the past 300 years. The aim is to understand legacies from past use patterns in present-day forest composition and consequences for conservation objectives from a landscape perspective. We analyze landscape development in cross-tabulation matrixes, building change trajectories. These trajectories are tested in linear models to explain the distribution of present-day landscape composition of coniferous, mixed, and deciduous forests >110 years. Of 49 tested change trajectories, 11 showed a significant association. Associations for mixed and coniferous forests were similar and linked to characteristics such as forest continuity, which characterized the studied landscape. Deciduous older forests did not show any association to forest continuity but were more likely to occur on areas that specifically shifted from forests with grazing in the 1720s to open impediment (likely indicating low tree coverage) in the 1850s. There were large shifts and spatial redistribution in ownerships over time. Use patterns and legacies varied between small- and large-scale ownership categories as well as within small-scale categories. The legacies found in the study indicate a complex origin of heterogeneous landscape elements such as older deciduous forests. Additionally, the origin of the legacies indicates a potential need to diversify conservation management based on the influence of past use patterns. Despite large inconsistencies in historical and contemporary data we argue that this type of analysis could be used to further understand the distribution of landscape elements important for conservation objectives.

Habitat fragmentation and the abandonment of former agricultural practices have led to extremely low dispersal rates for plant species growing in traditionally managed hay meadows in Sweden. Histor ...

Vicia pisiformis L. is a perennial leguminous plant with a main distribution in broadleaved forest-steppes of eastern Europe. The species is classified as endangered (EN) according to the IUCN red- ...

Question: We studied the patterns of plant species co-occurrence on three, nested, spatial scales in semi-natural grassland communities and explored the possible ecological processes underlying the ...

Horizontal gene transfer involves the non-sexual interspecific transmission of genetic material. Even if they are initially functional, horizontally transferred genes are expected to deteriorate into non-expressed pseudogenes, unless they become adaptively relevant in the recipient organism. However, little is known about the distributions of natural transgenes within wild species or the adaptive significance of natural transgenes within wild populations. Here, we examine the distribution of a natural plant-to-plant nuclear transgene in relation to environmental variation within a wild population.Festuca ovinais polymorphic for an extra (second) expressed copy of the nuclear gene (PgiC) encoding cytosolic phosphoglucose isomerase, with the extraPgiClocus having been acquired horizontally from the distantly related grass genusPoa.We investigated variation atPgiCin samples ofF. ovinafrom a fine-scale, repeating patchwork of grassland microhabitats, replicated within spatially separated sites. Even after accounting for spatial effects, the distributions ofF. ovinaindividuals carrying the additionalPgiClocus, and one of the enzyme products encoded by the locus, are significantly associated with fine-scale habitat variation. Our results suggest that thePgiCtransgene contributes, together with the unlinked ‘native’PgiClocus, to local adaptation to a fine-scale mosaic of edaphic and biotic grassland microhabitats.

We have recently found that the morphologically determined subspecies Gymnadenia conopsea ssp conopsea in Sweden includes early and late flowering individuals. We were interested in the interactions between the flowering time groups; if there were gene flow between them and if so this was detrimental or advantageous. A spatially mixed population of early and late flowering individuals was studied using three microsatellite loci. We measured patterns in genetic differentiation and inferred occurrence of hybridisation and introgression. Variation in flowering time, fertility and relative and absolute fruit set was measured. The pattern of introgression between flowering-time groups differed between loci. In two of the three investigated loci, allele separation was distinct between early and late flowering plants and one genetically obvious hybrid was infertile. In the third locus, several alleles were shared between the two flowering time variants. The degree of introgression was associated to fruit set failure, which was higher in the late flowering plants and lower in early flowering plants. A small group of early flowering individuals with somewhat delayed flowering compared to the main group was genetically distinct and had lower relative and absolute fruit set. This group was not genetically intermediate, but rather constituting an independent group, with lower fruit set possibly caused by absence of pollinators. There seem to be a strong barrier against introgression into the late flowering group which is kept genetically distinct and less diverse. The early flowering group is diverse, includes two subgroups and seems to benefit from gene flow.

Sphagnum (peatmoss) dominates huge areas of the Northern Hemisphere and acts as a significant carbon sink on a global scale, yet little is known about the genetic structure of Sphagnum populations. We investigated genetic structure within a population of the common peatmoss Sphagnum fuscum, to assess local patterns of genetic diversity and the spatial extent of clones. One hundred seventeen shoots were sampled from five transects in Fuglmyra, central Norway, and sequenced for three anonymous DNA regions. Five neighbourhood patches were marked along each transect, and from each patch, five stems were sampled for molecular analyses. Seventeen haplotypes could be distinguished and two major groups of haplotypes differed by 12 mutational steps. The two major haplotype groups differed significantly in microhabitat association along the distance to groundwater table and the pH gradients, indicating microhabitat differentiation. The haplotypes within these groups were all genetically similar, differing by one or two mutations. The most common haplotype occurred in four transects separated by 250-m distance. Most of the molecular variation in the population was found among transects, and within patches. Large dominating clones within each transect resulted in low variation explained by the among-patch-within-transect component of spatial structure. Mutation appears to account for a larger proportion of the population variation than recombination. Within the population, vegetative growth and asexual reproduction from gametophyte fragments dominate as the main reproductive mode.

Genetic differentiation between and within five varieties of Euphrasia stricta (var. brevipila, var. gotlandica, var. stricta, var. suecica and var. tenuis) on Gotland was investigated, using ampli ...

Genetic structure in two meadow varieties of Euphrasia stricta on the Baltic island of Gotland (Sweden) and implications for conservation

Within-population gene diversity (H-S) was estimated (using allozyme markers) for 16 populations of the perennial, outcrossing plant, Gypsophila fastigiata, on the Baltic island of Oland. The populations were characterized by data on extent, density, life-stages, and habitat diversity. Populations were classed as central or peripheral in relation to the distribution of ''alvar" (habitats with shallow, calcareous soils on limestone bedrock) on southern Oland. Three minimal adequate models were used to explain H-S and the proportions of juveniles and dead adults. In the first model, H-S was significantly lower in peripheral populations and there were no significant additional effects of other explanatory variables. The lower diversity in peripheral populations can be explained by a combination of genetic drift (in populations that vary in size in response to habitat fragmentation) and lower levels of interpopulation gene flow than in central populations. In the two life-stage models, peripheral populations had significantly larger proportions of both juveniles and dead adults indicating a greater demographic turnover than in the central populations. There were also significant effects of H-S and species diversity on the proportion of juveniles. The central or peripheral position of populations is the strop est predictor of both within-population gene diversity and life-stage dynamics in Oland G. fastigiata.

We studied genetic effects of the colonisation process during primary succession by analysing allozyme variation at a PGI locus in differently aged populations of Moehringia trinervia, which is a s ...

Tobacco smoking is a risk factor for numerous disorders, including cancers affecting organs outside the respiratory tract. Epidemiological data suggest that smoking is a greater risk factor for these cancers in males compared with females. This observation, together with the fact that males have a higher incidence of and mortality from most non–sex-specific cancers, remains unexplained. Loss of chromosome Y (LOY) in blood cells is associated with increased risk of nonhematological tumors. We demonstrate here that smoking is associated with LOY in blood cells in three independent cohorts [TwinGene: odds ratio (OR) = 4.3, 95% confidence interval (CI) = 2.8 to 6.7; Uppsala Longitudinal Study of Adult Men: OR = 2.4, 95% CI = 1.6 to 3.6; and Prospective Investigation of the Vasculature in Uppsala Seniors: OR = 3.5, 95% CI = 1.4 to 8.4] encompassing a total of 6014 men. The data also suggest that smoking has a transient and dose-dependent mutagenic effect on LOY status. The finding that smoking induces LOY thus links a preventable risk factor with the most common acquired human mutation.

1 The grass Festuca ovina is an important constituent of the species-rich 'alvar' grasslands on the Baltic island of Oland. Levels of allozyme polymorphism are high and variation is known to be correlated with habitat variation (soil moisture, pH and depth). 2 A 9-year field experiment on species diversity provided replicate plots (in three sites) that had been subjected to six different experimental treatments (control; N + P + K; P + K; N + K; K; water). 3 Samples of F. ovina were collected and analyses of deviance were used to investigate associations between allele frequencies, at each of four polymorphic loci, and the nutrient/water treatments. We also used the models to estimate predicted values for the alleles in different nutrient/water treatments and in interactions involving the nutrient/water treatments and additional explanatory variables (vegetation height and clipping). 4 There were significant allozyme frequency differences between samples of F. ovina from the six different nutrient/water treatments in the grassland experiment. Frequencies in the fertilized or watered plots had diverged from those in the control plots. There were also significant allele-habitat associations (after the removal of site effects), especially at the Pgi-2 locus. 5 Soil moisture was the only variable that was common to this study and an earlier study of variation in F. ovina in natural habitats. In natural populations, the Pgi-2-2 allele was significantly associated with soil moisture and was more common in dry habitats. Our findings that the frequency of the Pgi-2-2 allele was significantly affected by the nutrient/water treatments, and that it was rarest in the treatment that involved the addition of extra water, were therefore as predicted. 6 The study supports the conclusion, from an earlier study of populations in unmanipulated grassland habitats, that selection is contributing to the fine-scale patterning of genetic variation in the alvar populations of F. ovina.

Genetic variation at alcohol dehydrogenase and phosphoglucose isomerase loci inBromus hordeaceushas in an earlier study been found to show substantial microgeographic spatial structuring. The present study reports differences in fitness related characters between the enzyme genotypes, both from a field study and a greenhouse experiment. The field study showed overall differences in seed set between allozyme genotypes and also thatPgi-1b genotypes differed in number of seeds set at different levels of herb cover in their habitat. In the greenhouse, dry, normal or flooded conditions were applied. Seeds from individuals with theAdh-1b-11 genotype matured faster in the dry and slower in the flooded treatments than did seeds from individuals with theAdh-1b-22 genotype. Individuals containingPgi-1b-1f1f alleles andAdh-1b-11 alleles are more plastic than individuals with other allele combinations, meaning that allozyme variation could partly explain what could be seen as adaptive phenotypic plasticity. Mean seed weight was different between dry and flooding treatments forPgi-1b genotypes. There were also direct effects of allozyme genotype on the probability of survival, total plant weight, weight of reproductive parts, seed weight, days to seed maturation and the percentage of reproductive parts out of the total plant weight.

We investigated allozyme variation and phenotypic variation in leaf shape in 15 populations of the shrub Hippocrepis emerus (Leguminosae) from the three isolated, regional populations in Scandinavia and analysed patterns of differentiation and the hierarc

Tick-borne encephalitis virus (TBEV) is a flavivirus with major impact on global health. The geographical TBEV distribution is expanding, thus making it pivotal to further characterize the natural virus populations. In this study, we completed the earlier partial sequencing of a TBEV pulled out of a pool of RNA extracted from 115 ticks collected on Toro in the Stockholm archipelago. The total RNA was sufficient for all sequencing of a TBEV genome (Toro-2003), without conventional enrichment procedures such as cell culturing or suckling mice amplification. To our knowledge, this is the first time that the genome of TBEV has been sequenced directly from an arthropod reservoir. The Toro-2003 sequence has been characterized and compared with other TBE viruses. In silico analyses of secondary RNA structures formed by the two untranslated regions revealed a temperature-sensitive structural shift between a closed replicative form and an open AUG accessible form, analogous to a recently described bacterial thermoswitch. Additionally, novel phylogenetic conserved structures were identified in the variable part of the 3'-untranslated region, and their sequence and structure similarity when compared with earlier identified structures suggests an enhancing function on virus replication and translation. We propose that the thermo-switch mechanism may explain the low TBEV prevalence often observed in environmentally sampled ticks. Finally, we were able to detect variations that help in the understanding of virus adaptations to varied environmental temperatures and mammalian hosts through a comparative approach that compares RNA folding dynamics between strains with different mammalian cell passage histories.

Petrorhagia prolifera is an annual, predominantly self-pollinating herb with a decreasing European distribution. The present article describes a survey of variation in populations sampled from 18 sites in the province of Skane (South Sweden) and on the Baltic islands of Oland and Gotland. Electrophoresis often enzyme systems (20 putative loci) revealed allelic variation at only two loci. A third locus showed phenotypic variation among sites that was not reliably interpretable in terms of allozymes. Partitioning of allelic diversity into its within- and among-individual, -site and -regional components showed that most diversity is stored among sites. There is little differentiation among regional metapopulations and, although three sites showed within-population variation, no heterozygous individuals were encountered. Variation in seed shape was analysed using automated image acquisition and shape description techniques. Partitioning of the morphological diversity was similar to that of allelic diversity (diversity among-sites-within-regions > diversity among-individuals-within-sites > diversity among-regions > within-individual diversity). The rate of selfing in P. prolifera is estimated to be more than 94%. The mosaic structuring of diversity in P. prolifera is interpreted in terms of breeding system and random processes during the species' history of colonization and/or range disjunction.

We have recently found that the morphologically determined subspecies Gymnadenia conopsea ssp conopsea in Sweden includes early and late flowering individuals. We were interested in the interactions between the flowering time groups; if there were gene flow between them and if so this was detrimental or advantageous. A spatially mixed population of early and late flowering individuals was studied using three microsatellite loci. We measured patterns in genetic differentiation and inferred occurrence of hybridisation and introgression. Variation in flowering time, fertility and relative and absolute fruit set was measured. The pattern of introgression between flowering-time groups differed between loci. In two of the three investigated loci, allele separation was distinct between early and late flowering plants and one genetically obvious hybrid was infertile. In the third locus, several alleles were shared between the two flowering time variants. The degree of introgression was associated to fruit set failure, which was higher in the late flowering plants and lower in early flowering plants. A small group of early flowering individuals with somewhat delayed flowering compared to the main group was genetically distinct and had lower relative and absolute fruit set. This group was not genetically intermediate, but rather constituting an independent group, with lower fruit set possibly caused by absence of pollinators. There seem to be a strong barrier against introgression into the late flowering group which is kept genetically distinct and less diverse. The early flowering group is diverse, includes two subgroups and seems to benefit from gene flow.

Smoking of tobacco is a major preventable environmental risk factor related to human health. Smoking killed about 100 million people during the 20th century and is projected to kill one billion people during this century, assuming that the current frequency of smoking is maintained. Lung cancer is the prime cause of cancer-associated death in relation to smoking. However, it is less well appreciated that smoking also causes tumors outside the respiratory tract, which are predominant in men, and cumulatively roughly as common as lung cancer. Moreover, it is known that males have a higher incidence and mortality from most sex-unspecific cancers, regardless of smoking status, and this fact is largely unexplained by known risk factors. We have recently shown that a male specific risk factor, acquired mosaic loss of chromosome Y (LOY) in non-cancerous blood cells, is associated with an increased risk of non-hematological tumors among aging males. Median survival among men with LOY was 5.5 years shorter [1]. We demonstrate here that smoking is associated with LOY in blood cells in three independent cohorts (TwinGene: odds ratio [OR] = 4.3, 95% CI = 2.8-6.7; ULSAM: OR = 2.4, 95% CI = 1.6-3.6; and PIVUS: OR = 3.5, 95% CI = 1.4-8.4) encompassing in total 6014 men. Our data also support a transient and dose-dependent mutagenic effect from smoking on LOY-status [2]. Thus, smoking may induce LOY, linking the most common acquired human mutation with a severe preventable risk factor. Our results could explain the observed sex differences and why smoking seems a greater risk factor for cancer in men than women. The molecular mechanisms behind these observations are not well understood, but LOY appears a strong and male-specific risk factor. Follow up studies are required to understand how cellular Y chromosome deficiency in normal blood cells might cause risk for cancer. We hypothesize that the Y-chromosome loss may be skewed towards, and exert negative effect on, a specific population of immune cells that are responsible for immunosurveillance. Selected references: 1. Forsberg LA, Rasi C, Malmqvist N, Davies H, Pasupulati S, Pakalapati G, Sandgren J, de Stahl TD, Zaghlool A, Giedraitis V, Lannfelt L, Score J, Cross NC, Absher D, Janson ET, Lindgren CM, Morris AP, Ingelsson E, Lind L, Dumanski JP: Mosaic loss of chromosome Y in peripheral blood is associated with shorter survival and higher risk of cancer, Nature Genetics 2014, 46:624-628. 2. Dumanski J, Rasi C, Lönn M, Davies H, Ingelsson M, Giedraitis V, Lannfelt L, Magnusson P, Lindgren C, Morris A, Cesarini D, Johannesson M, Tiensuu Janson E, Lind L, Pedersen N, Ingelsson E, Forsberg L: Smoking is associated with mosaic loss of chromosome Y, Science 2014, in press. Citation Format: Jan P. Dumanski, Chiara Rasi, Mikael Lönn, Hanna Davies, Martin Ingelsson, Vilmantas Giedraitis, Lars Lannfelt, Patrik KE Magnusson, Cecilia M. Lindgren, Andrew P. Morris, David Cesarini, Magnus Johannesson, Eva Tiensuu Janson, Lars Lind, Nancy L. Pedersen, Erik Ingelsson, Lars A. Forsberg. Smoking is associated with mosaic loss of chromosome Y. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4683. doi:10.1158/1538-7445.AM2015-4683

We investigated patterns of allozyme variation in demes of the grass Briza media in semi-natural grassland fragments within a mosaic agricultural landscape on the Baltic island of Öland. In the study area, Briza is both a characteristic species of old pastures and an early colonizer of young grasslands developing on previously forested or arable sites. 2 Generalized linear models revealed that descriptors of both present landscape structure and past grassland history are significant determinants of genetic variation in the Briza demes. Genetic structure and levels of within-deme diversity are influenced by the size of grassland fragments, the type of habitat surrounding the grasslands, the size/spatial extent of the demes, the geographic position of the demes and the historical continuity of the grassland fragments. 3 Gene diversity (H) was higher in demes from grassland polygons with a high proportion of adjacent grassland, higher in the more extensive demes, and decreased northwards within the study area. 4 The negative association between the inbreeding coefficient (FIS) and grassland continuity is interpreted in terms of a two-stage colonization process: recruitment into young grasslands leads initially to spatial patchiness, but subsequent selection in maturing pastures occurs within an increasingly uniform and dense sward. 5 Despite a weak overall genetic structure (as indicated by Bayesian cluster analysis) the between-deme FST was significant. Linear discriminant analysis of within-deme allele frequencies grouped the demes according to the age and previous land-use history of their grassland polygons. The convergence of the allele frequency profiles in the younger grasslands towards those of the old grasslands is consistent with convergence of selective regimes as pastures mature towards an increasingly uniform, dense sward and characteristic species assemblage. 6 The genetic composition of demes of a grassland species appears to be influenced by the process of plant community convergence during grassland development – complementing the recent finding that convergence of species composition in experimental assemblages of grassland plants is dependent on the genotypic composition of the component species.

Using fast-evolving microsatellites, more slowly evolving ITS markers and performing habitat analyses, we demonstrated a drastic genetic divergence and significant habitat differentiation between early- and late-flowering variants of plants morphologically belonging to Gymnadenia conopsea ssp conopsea. The two phenological variants can either be found in separate or in mixed populations. Information from microsatellite markers and ITS sequences indicated the occurrence of an early historical split between the two flowering-time variants, a split that has been maintained until the present time even within sympatric populations. Early-flowering variants were also far more genetically diverse, had more alleles per microsatellite locus and a wider habitat amplitude than late-flowering variants. As a comparison, we included G. odoratissima in the sequencing study. We found G. odoratissima to be most closely related to the early-flowering type. This indicates a more ancient divergence event between the two flowering-time variants within G. conopsea ssp conopsea than between the two different species G. odoratissima and the early-flowering variant of G. conopsea. Possible explanations to the results arrived at and possible mechanisms maintaining the genetic separation are discussed.

Relationships between allozyme differentiation, habitat variation and individual reproductive success were examined in local populations of a perennial herb, Gypsophila fastigiata, on the Baltic island of Oland (Sweden). Relatively little (c. 2%) of the total allozyme diversity in this largely outcrossing species is explained by differentiation between sites tens of kilometres apart. The low level of geographic differentiation suggests that gene flow between sites is, or has recently been, extensive. Yet the component of allozyme diversity due to differentiation between plots (only tens of meters apart) within sites is 3 times larger than the between-site component of diversity. Allozyme variation, especially at the Pgi-2 locus, is significantly associated with habitat variation within sites. Different allele x habitat combinations for the Pgi-2 locus are associated with differences in individual reproductive fitness. Differential selection in different local habitats may thus contribute to the fine-scale structuring of genetic diversity within sites.

Vicia pisiformis L. is a perennial leguminous plant with a main distribution in broadleaved forest-steppes of eastern Europe. The species is classified as endangered (EN) according to the IUCN red-lists in both Norway and Sweden, due to severe fragmentation, small population sizes and continuing population decline. The populations on the Scandinavian Peninsula constitute the northern limit of the species distribution and are mostly restricted to warm stony slopes with predominantly southern aspects. In this study we used the AFLP method, which is a high-resolution genetic fingerprint method. Samples were collected from 22 Scandinavian populations. The overall genetic structure was analysed in an AMOVA, in a Mantel test and through constrained correspondence analysis (CCA). The ordination scores representing non-geographic genetic divergence were extracted from the CCA and analysed in a linear model using habitat variables and population size as explanatory variables. We found (i) a strong geographic structure, (ii) significant genetic divergence between populations, (iii) that this genetic divergence remained significant even after removing the effect of geography in a partial CCA and (iv) that the remaining non-geographic part of genetic divergence (distance from the ordination centre) was associated with aspect, populations with a northern aspect were more genetically divergent. Aspect explains more variation than population size and is the only variable retained in the minimal adequate model. We suggest that local adaptation has caused this divergence from an expected geographical pattern of genetic variation. This explanation is further supported by the association between aspect and specific AFLP fragments.

1 If different genotypes have different relative fitnesses in different habitats, genetic diversity may be maintained in local populations by habitat selection. The spatial structuring of genetic variation within plant populations will thus be associated

Genetic variation at alcohol dehydrogenase and phosphoglucoisomerase loci in Bromus hordeaceus on the Baltic island of Oland shows substantial spatial structuring among sites several km apart but also among plots within sites on a scale less than ten m. Oland habitats occupied by B. hordeaceus consist of a fine-scale mosaic in which thin soils on well-drained calcareous bedrock are interspersed with depressions containing deeper soil and subject to seasonal water logging. Among sites, the frequency of the Adh-1b-S allele was significantly associated with soil depth and with the cover of mosses and of grasses. The frequency of the Pgi-1b-F allele was significantly associated with soil depth and the Pgi-1b-M allele was significantly associated with soil depth and with the cover of mosses, lichen and grasses (...)

Connectivity plays an important role in shaping the genetic structure and in evolution of local adaptation. In the marine environment barriers to gene flow are in most cases caused by gradients in environmental factors, ocean circulation and/or larval behavior. Despite the long pelagic larval stages, with high potential for dispersal many marine organisms have been shown to have a fine scale genetic structuring. In this study, by using a combination of high-resolution genetic markers, species hybridization data and biophysical modeling we can present a comprehensive picture of the evolutionary landscape for a keystone species in the Baltic Sea, the blue mussel. We identified distinct genetic differentiation between the West Coast, Baltic Proper and Bothnian Sea regions, with lower gene diversity in the Bothnian Sea. Oceanographic connectivity together with salinity and to some extent species identity provides explanations for the genetic differentiation between the West Coast and the Baltic Sea (Baltic Proper and Bothnian Sea). The genetic differentiation between the Baltic Proper and Bothnian Sea cannot be directly explained by oceanographic connectivity, species identity or salinity, while the lower connectivity to the Bothnian Sea may explain the lower gene diversity.