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19 Pág., Microgeographical adaptation occurs when the effects of directional selection persist despite gene flow. Traits and genetic loci under selection can then show adaptive divergence, against the backdrop of little differentiation at other traits or loci. How common such events are and how strong the selection is that underlies them remain open questions. Here, we discovered and analysed microgeographical patterns of genomic divergence in four European and Mediterranean conifers with widely differing life-history traits and ecological requirements (Abies alba MIll., Cedrus atlantica [Endl.] Manetti, Pinus halepensis Mill. and Pinus pinaster Aiton) by screening pairs from geographically close forest stands sampled along steep ecological gradients. We inferred patterns of genomic divergence by applying a combination of divergence outlier detection methods, demographic modelling, Approximate Bayesian Computation inferences and genomic annotation to genomic data. Surprisingly for such small geographical scales, we showed that selection is strong in all species but generally affects different loci in each. A clear signature of selection was systematically detected on a fraction of the genome, of the order of 0.1%-1% of the loci depending on the species. The novel modelling method we designed for estimating selection coefficients showed that the microgeographical selection coefficient scaled by population size (Ns) was 2-30. Our results convincingly suggest that selection maintains within-population diversity at microgeographical scales in spatially heterogeneous environments. Such genetic diversity is likely to be a major reservoir of adaptive potential, helping populations to adapt under fluctuating environmental conditions., Agence Nationale de la Recherche, Grant/ Award Number: FLAG project (ANR-12- ADAP-0007-01); European Commission, Grant/Award Number: TOPWOOD project (MSCA-RISE-2014-645654- TOPWOOD) and grant agreement No. 676876 (GenTree); Ministère de l'Écologie, du Développement Durable et de l'Énergie, Grant/Award Number: GRAAL project (10-MCGOT-GICC-8-CVS-139)

International audience; Background - Staphylococcus aureus (SA) has been extensively studied as causative microorganism of surgical prosthetic-valve infective endocarditis (IE). However, scarce evidence exists on SA IE after transcatheter aortic valve replacement (TAVR). Methods - Data were obtained from the Infectious Endocarditis After TAVR International Registry, including patients with definite IE after TAVR from 59 centres in 11 countries. Patients were divided into 2 groups according to microbiologic etiology: non-SA IE vs SA IE. Results - SA IE was identified in 141 patients out of 573 (24.6%), methicillin-sensitive SA in most cases (115/141, 81.6%). Self-expanding valves were more common than balloon-expandable valves in patients presenting with early SA IE. Major bleeding and sepsis complicating TAVR, neurologic symptoms or systemic embolism at admission, and IE with cardiac device involvement (other than the TAVR prosthesis) were associated with SA IE (P < 0.05 for all). Among patients with IE after TAVR, the likelihood of SA IE increased from 19% in the absence of those risk factors to 84.6% if ≥ 3 risk factors were present. In-hospital (47.8% vs 26.9%; P < 0.001) and 2-year (71.5% vs 49.6%; P < 0.001) mortality rates were higher among patients with SA IE vs non-SA IE. Surgery at the time of index SA IE episode was associated with lower mortality at follow-up compared with medical therapy alone (adjusted hazard ratio 0.46, 95% CI 0.22-0.96; P = 0.038). Conclusions - SA IE represented approximately 25% of IE cases after TAVR and was associated with very high in-hospital and late mortality. The presence of some features determined a higher likelihood of SA IE and could help to orientate early antibiotic regimen selection. Surgery at index SA IE was associated with improved outcomes, and its role should be evaluated in future studies.

Trees play a key role in the structure and function of many ecosystems worldwide. In the Mediterranean Basin, forests cover approximately 22% of the total land area hosting a large number of endemics (46 species). Despite its particularities and vulnerability, the biodiversity of Mediterranean trees is not well known at the taxonomic, spatial, functional, and genetic levels required for conservation applications. The WOODIV database fills this gap by providing reliable occurrences, four functional traits (plant height, seed mass, wood density, and specific leaf area), and sequences from three DNA-regions (rbcL, matK, and trnH-psbA), together with modelled occurrences and a phylogeny for all 210 Euro-Mediterranean tree species. We compiled, homogenized, and verified occurrence data from sparse datasets and collated them on an INSPIRE-compliant 10 × 10 km grid. We also gathered functional trait and genetic data, filling existing gaps where possible. The WOODIV database can benefit macroecological studies in the fields of conservation, biogeography, and community ecology.

International audience; Aortic valve stenosis (AS) shares similarities with the atherosclerotic process but little is known about the effect of the mechanical properties of large arteries on outcome in patients with AS. The aims of this study were (1) to determine the relationship between indexes of carotid stiffness/compliance and the severity of AS and (2) to identify whether local arterial stiffness is independently associated with mortality. 133 patients with moderate to severe isolated AS and preserved LV ejection fraction (LVEF) were included. All underwent transthoracic echocardiography and local carotid stiffness evaluation by means of high-definition echo-tracking ultrasound with the calculation of stiffness/compliance parameters included augmentation index (AIx). None of the carotid stiffness parameters were significantly associated with AS severity parameters. During a mean follow-up of 51.6 ± 39.4 months, 70 patients received aortic valve replacement, 45 died and 18 were alive with no surgery. Who died were older (79.2 ± 6.9 vs. 73 ± 8.8 years, p < 0.0001), had higher carotid AIx (21.3 ± 14 vs. 16 ± 12%, p = 0.028). In multivariate Cox regression analysis AIx was independently associated with mortality (HR 1.048, 95% CI 1.01-1.07, p = 0.001), also after inclusion of age and creatinine. There was a significant association between the level of AIx and mortality in those patients who did not have surgery (p = 0.016). In severe AS and a normal LVEF, carotid AIx measured by echo-tracking system was independently associated with death. No relationship between AS severity and local carotid stiffness was found. These data emphasize the importance of arterial stiffness has a hallmark of long-term atherosclerotic burden and impaired prognosis.

International audience; Aleppo pine (Pinus halepensis Mill.) has been studied with genetic markers over the last 20 years, in order to decipher its evolutionary history at both full-distribution and local scales, incorporating new insights as molecular technologies evolve. In this process, knowledge has accumulated on population diversity and structure, demographic history, gene flow and adaptation. This chapter provides an historical overview of the accumulated knowledge on the evolutionary history of Aleppo pine based on molecular markers, and outlines what still remains to be done to fully understand how this species has adapted to its current distribution, and how it will be able to withstand ongoing selective pressures under a Mediterranean climate.

International audience; Resumé : The 4TREE Axiom 50K SNP array is one of the main deliverables of the H2020 project B4EST which aims at transferring know-how and tools to improve breeding for production, resilience and diversity of forest trees. This array is developed for: Populus sp, Fraxinus sp, Pinus pinaster and Pinus pinea. It is based on de novo sequencing resources and existing genomic resources of loci of interest for breeders. 4TREE is primarily aimed at breeders by providing low genotyping costs for economically important species in Europe, fostering collaboration between breeding programs across Europe. One of its first uses will be genome wide association studies and genomic predictions, being also extremely useful for monitoring and characterizing novel sources of variation. Material/ Methods : The 4Tree array will be designed after the screening of 420K SNP. Except for the orphan species P. pinea, SNP were identified from existing genomic resources: whole genome and RNA sequencing, exome capture, SNP arrays. SNP gathered by these resources were filtered for inclusion in a screening array of 420K (105K/species) and checked over a panel of 480 samples (120/species). SNP without other polymorphisms within 30bp flanking sequences were preferentially selected and those in unique region were prioritized, limiting A/T and C/G which require more space on the array. The selection included several SNP in candidate genes or regions found via transcriptomic, QTL and GWAS analysis. Results : For P. pinea, 128K SNPs were submitted to ThermoFisher, resulting in 37K recommended SNPs for the screening array. P. pinaster submitted 197K SNPs (5K SNPs from Plomion et al. 2016), leading to 140K inclusions in the screening array, including several from candidate genes for abiotic and biotic stress. For Fraxinus sp, 126K SNP were selected from the 327K scored. SNPs were selected in order to prioritize candidate SNPs associated to dieback disease tolerance and incompatibility (Stocks & Metheringham et al. 2019). SNPs were additionally selected according to the genomic coverage (maximum possible representation of genes and scaffolds with respect to the reference genome). For Populus, a subset of SNPs was identified for two species: P. nigra and P. deltoides. These SNPs were either species specific or shared between the two species. For P. nigra, SNPs from a previous array (Faivre-Rampant et al. 2016) and from candidate regions from GWAS were also selected. The final coverage of the genome was 100 SNP/Mb with a ratio of genic and intergenic SNPs of 60/40%. In total, 3 000K SNP were submitted to ThermoFisher for Populus to select 120,500 for the screening array. Conclusion: From this screening genotyping, 12.5K high value SNPs per species will be retained for the final array 4TREE dedicated to gene discovery, pre-breeding monitoring of diversity and genomic selection studies in B4EST. This final array will be a highly valuable genome-assisted breeding tool, made commercially available for cost effective HT genotyping for four important tree species in Europe.

International audience; We produced the first time-calibrated phylogeny of all 64 native tree genera occurring on the European side of the Mediterranean Basin. This phylogeny is based on 3 plastid DNA sequences (rbcL matK and trnH-psbA), 4 recognized fossil dates and 10 secondary calibrations. Based on the inferred topology, we then tested whether the investigated tree flora exhibits phylogenetic clustering in both life-history traits known to influence reproduction and species' vulnerability to extinction. Our topology and the estimated dates mostly conform to published partial phylogenies and are highly congruent with the Angiosperm Phylogeny Group classification except for some minor incongruences including the still debated phylogenetic position of Magnoliids. The four strictly endemic genera of the Mediterranean Basin (Chamaerops, Phillyrea, Spartium and Tetraclinis) all showed emergence dates (11-72 Ma) long before the onset of the Mediterranean climate. We did not find any imprints of phylogenetic sorting processes on the life-history traits we studied, except for the mode of seed dispersal, which showed a clustered distribution across our topology. The presence of species at risk of potential extinction within a given genus was randomly distributed along the phylogenetic tree. Species with deficient data were significantly nested within a few of the most recently evolved angiosperm genera. Our analysis closes knowledge gaps and provides a valuable basis for studying the biogeo-graphical and ecological processes that have generated the Mediterranean tree flora. It can also inform conservation planning strategies that aim at broadening traditional taxonomy-focused perspectives with components of evolutionary history and phylogenetic singularity.

Sweet cherry (Prunus avium L.) trees are both economically important fruit crops but also important components of natural forest ecosystems in Europe, Asia and Africa. Wild and domesticated trees currently coexist in the same geographic areas with important questions arising on their historical relationships. Little is known about the effects of the domestication process on the evolution of the sweet cherry genome. We assembled and annotated the genome of the cultivated variety "Big Star*" and assessed the genetic diversity among 97 sweet cherry accessions representing three different stages in the domestication and breeding process (wild trees, landraces and modern varieties). The genetic diversity analysis revealed significant genome-wide losses of variation among the three stages and supports a clear distinction between wild and domesticated trees, with only limited gene flow being detected between wild trees and domesticated landraces. We identified 11 domestication sweeps and five breeding sweeps covering, respectively, 11.0 and 2.4 Mb of the P. avium genome. A considerable fraction of the domestication sweeps overlaps with those detected in the related species, Prunus persica (peach), indicating that artificial selection during domestication may have acted independently on the same regions and genes in the two species. We detected 104 candidate genes in sweep regions involved in different processes, such as the determination of fruit texture, the regulation of flowering and fruit ripening and the resistance to pathogens. The signatures of selection identified will enable future evolutionary studies and provide a valuable resource for genetic improvement and conservation programs in sweet cherry.

International audience

The Mediterranean stone pine is currently on its way to domestication. Its genuine Mediterranean pine nuts are among the most expensive nuts in the world because they are mainly wild-collected from pine forests and woodlands. Despite the wide current distribution of stone pine over the whole Mediterranean biome, old-growth forests are scarce, often associated locally with dynamics on lose sands, coastal dunes or former estuary marshes. The species has been found to be genetically depauperate, putatively due to a population bottleneck in a local refugium during the Last Glacial Maximum confirmed in southern Iberia, and a possibly anthropic range expansion during Holocene. Only recently, cone harvesting and processing mechanisation have allowed for profitable pine nut production from orchard plantations. In Spain and Portugal, first elite clones have been registered for their use as grafted orchard crop.

International audience; Detecting the molecular basis of local adaptation and identifying selective drivers is still challenging in nonmodel species. The use of purely population genetic approaches is limited by some characteristics of genetic systems, such as pleiotropy and polygenic control, and parallel evidence from phenotypic‐based experimental comparisons is required. In long‐lived organisms, the detection of selective pressures might also be precluded by evolutionary lag times in response to the environment. Here, we used the English yew to showcase an example of a multiscale integrative approach in a nonmodel species with limited plant and genomic resources. We combined information from two independent sources, phenotypes in a common environment and genomic data in natural populations, to investigate the signature of selection. Growth differences among populations in a common environment, and phenological patterns of both shoot elongation and male strobili maturation, were associated with climate clines, providing evidence for local adaptation and guiding us in the selection of populations for genomic analyses. We used information on over 25,000 SNPs from c. 1,200 genes to infer the demographic history and to test for molecular signatures of selection at different levels: SNP, gene, and biological pathway. Our results confirmed an overall demographic history of population decline, but we also found evidence for putative local adaptation at the molecular level. We identified or confirmed several candidate genes for positive and negative selection in forest trees, including the pseudo‐response regulator 7 (PRR7), an essential component of the circadian clock in plants. In addition, we successfully tested an approach to detect polygenic adaptation in biological pathways, allowing us to identify the flavonoid biosynthesis pathway as a candidate stress‐response pathway that deserves further attention in other plants. Finally, our study contributes to the emerging view that explaining contemporary standing genetic variation requires considering adaptation to past climates, especially for long‐lived trees.

Plant populations can undergo very localized adaptation, allowing widely distributed populations to adapt to divergent habitats in spite of recurrent gene flow. Neotropical trees whose large and undisturbed populations often span a variety of environmental conditions and local habitats are particularly good models to study this process. Here, we carried out a genome scan for selection through whole-genome sequencing of pools of populations, sampled according to a nested sampling design, to evaluate microgeographic adaptation in the hyperdominant Amazonian tree Eperua falcata Aubl. (Fabaceae). A high-coverage genomic resource of 250 Mb was assembled de novo and annotated, leading to 32,789 predicted genes. 97,062 bi-allelic SNPs were detected over 25,803 contigs, and a custom Bayesian model was implemented to uncover candidate genomic targets of divergent selection. A set of 290 divergence outlier SNPs was detected at the regional scale (between study sites), while 185 SNPs located in the vicinity of 106 protein-coding genes were detected as replicated outliers between microhabitats within regions. These genes potentially underlie ecologically important phenotypes and indicate that adaptation to microgeographic habitat patchiness would affect genomic regions involved in a variety of physiological processes, among which plant response to stress (for e.g., oxidative stress, hypoxia and metal toxicity) and biotic interactions. Identification of genomic targets of microgeographic adaptation in the Neotropics is consistent with the hypothesis that local adaptation is a key driver of ecological diversification, operating across multiple spatial scales, from large (i.e. regional) to microgeographic (i.e. landscape) scales.

Fragmentation acting over geological times confers wide, biogeographical scale, genetic diversity patterns to species, through demographic and natural selection processes. To test the effects of historical fragmentation on the genetic diversity and differentiation of a major European forest tree and to resolve its demographic history, we describe and model its spatial genetic structure and gene genealogy. We then test which Pleistocene event, whether recent or ancient, could explain its widespread but patchy geographic distribution using population genetic data, environmental data and realistic demographic timed scenarios.The taxon of interest is a conifer forest tree,Pinus nigra(Arnold), the European black pine, whose populations are located in the mountains of southern Europe and North Africa, most frequently at mid-elevation. We used a set of different genetic markers, both neutral and potentially adaptive, and either bi-parentally or paternally inherited, and we sampled natural populations across the entire range of the species. We analysed the data using frequentist population genetic methods as well as Bayesian inference methods to calibrate realistic, demographic timed scenarios.Species with geographically fragmented distribution areas are expected to display strong among-population genetic differentiation and low within-population genetic diversity. Contrary to these expectations, we show that the current diversity ofPinus nigraand its weak genetic spatial structure are best explained as resulting from late Pleistocene or early Holocene fragmentation of one ancestral population into seven genetic lineages, which we found to be the main biogeographical contributors of the natural black pine forests of today. Gene flow among the different lineages is strong across forests and many current populations are admixed between lineages. We propose to modify the currently accepted international nomenclature made of five subspecies and name these seven lineages using regionally accepted subspecies-level names.HighlightsThe European black pine,Pinus nigra(Arnold), has a weak spatial genetic structure.Gene flow among populations is frequent and populations are often of admixed origin.Current genealogies result from recent, late Pleistocene or Holocene events.Seven modern genetic lineages emerged from divergence and demographic contractions.These seven lineages warrant a revision of subspecies taxonomic nomenclature.

This paper explores the structure groups $G_{(X,r)}$ of finite non-degenerate set-theoretic solutions $(X,r)$ to the Yang-Baxter equation. Namely, we construct a finite quotient $\overline{G}_{(X,r)}$ of $G_{(X,r)}$, generalizing the Coxeter-like groups introduced by Dehornoy for involutive solutions. This yields a finitary setting for testing injectivity: if $X$ injects into $G_{(X,r)}$, then it also injects into $\overline{G}_{(X,r)}$. We shrink every solution to an injective one with the same structure group, and compute the rank of the abelianization of $G_{(X,r)}$. We show that multipermutation solutions are the only involutive solutions with diffuse structure group; that only free abelian structure groups are biorderable; and that for the structure group of a self-distributive solution, the following conditions are equivalent: biorderable, left-orderable, abelian, free abelian, torsion free., 32 pages. Final version. Accepted for publication in Proc. Edinburgh Math. Soc

Demographic and evolutionary history of the European black pine (Pinus nigra Arn). Réunion du groupe AFORGEN

International audience

The European black pine (Pinus nigra Arn.) is an ecologically and economically important conifer discontinuously and often patchily distributed across different ecological environments and climatic conditions around the Mediterranean Basin. Many studies aiming at understanding the evolutionary history of the species have been carried out, particularly in the hope of resolving the taxonomy of this collective species where many subspecies have been described. So far, neither morphology, enzyme, and metabolite polymorphism nor DNA marker studies have been able to converge on a single taxonomy, and the evolutionary history of the European black pine remains unclear. To date, nuclear microsatellites (nSSRs) are not available for P. nigra. In this work we designed two multiplexes of eight and six nSSRs each, both characterized by high amplification quality and polymorphism. Nine nSSRs were specifically developed for the European black pine starting from six transcriptomes sequenced using Next Generation Sequencing (NGS) techniques following the Illumina method, while five previously developed for other pines were successfully transferred to P. nigra. The mean number of alleles per locus was 5.9, and the observed heterozygosity ranged between 0.341 and 0.875. F ST was statistically significant for all loci, and Bayesian clustering approaches revealed a geographically meaningful population structure. We thus show this set of 14 nSSRs to be highly informative for population genetic studies and of significant interest to resolve the taxonomy of the European black pine.

International audience

Background and Aims The recurrence of wildfires is predicted to increase due to global climate change, resulting in severe impacts on biodiversity and ecosystem functioning. Recurrent fires can drive plant adaptation and reduce genetic diversity; however, the underlying population genetic processes have not been studied in detail. In this study, the neutral and adaptive evolutionary effects of contrasting fire regimes were examined in the keystone tree species Pinus halepensis Mill. (Aleppo pine), a fire-adapted conifer. The genetic diversity, demographic history and spatial genetic structure were assessed at local (within-population) and regional scales for populations exposed to different crown fire frequencies. Methods Eight natural P. halepensis stands were sampled in the east of the Iberian Peninsula, five of them in a region exposed to frequent crown fires (HiFi) and three of them in an adjacent region with a low frequency of crown fires (LoFi). Samples were genotyped at nine neutral simple sequence repeats (SSRs) and at 251 single nucleotide polymorphisms (SNPs) from coding regions, some of them potentially important for fire adaptation. Key Results Fire regime had no effects on genetic diversity or demographic history. Three high-differentiation outlier SNPs were identified between HiFi and LoFi stands, suggesting fire-related selection at the regional scale. At the local scale, fine-scale spatial genetic structure (SGS) was overall weak as expected for a wind-pollinated and wind-dispersed tree species. HiFi stands displayed a stronger SGS than LoFi stands at SNPs, which probably reflected the simultaneous post-fire recruitment of co-dispersed related seeds. SNPs with exceptionally strong SGS, a proxy for microenvironmental selection, were only reliably identified under the HiFi regime. Conclusions An increasing fire frequency as predicted due to global change can promote increased SGS with stronger family structures and alter natural selection in P. halepensis and in plants with similar life history traits., This work was supported by the following projects financed by the Spanish Ministry of Science and Innovation (MICINN) VAMPIRO [CGL2008-05289-C02-01/02], LinkTree [EUI200-03713] under the ERAnet-BiodivERsA call, TREVOL [CGL2012-39938-C02-00/01] and AFFLORA [CGL2012-40129-C02-02], a PhD scholarship to K.B.B. [FPI: BES-2009-015443] and a ‘Ramón y Cajal’ fellowship [RYC2009-04537] to M.H. G.G.V. was also supported by the Italian MIUR project ‘Biodiversitalia’ [RBAP10A2T4]. M.H. acknowledges a Marie-Curie Intra-European fellowship [PIEF-GA-2012-329088] and research funding from the Research Council of Norway [203822/E40]

This book looks at the history of work and the meanings that are attached to it over time. Taking as its basis a number of international surveys and interviews conducted in Europe, the authors consider the significance of work for Europeans today.Over the years the meaning of work has changed. It has become more highly diversified, and it is today invested with high expectations that conflict with organisational developments and the changing nature of the labour market. The authors use a generational perspective to explore whether it is possible to reconcile the contemporary “ethos” of work, especially with regards to women and young people, with organisations that are increasingly under pressure to be profitable and productive.

Wood is a renewable resource that can be employed for the production of second generation biofuels by enzymatic saccharification and subsequent fermentation. Knowledge on how the saccharification potential is affected by genotype-related variation of wood traits and drought is scarce. Here, we used three Populus nigra L. genotypes from habitats differing in water availability to (i) investigate the relationships between wood anatomy, lignin content and saccharification and (ii) identify genes and co-expressed gene clusters related to genotype and drought-induced variation in wood traits and saccharification potential. The three poplar genotypes differed in wood anatomy, lignin content and saccharification potential. Drought resulted in reduced cambial activity, decreased vessel and fiber lumina, and increased the saccharification potential. The saccharification potential was unrelated to lignin content as well as to most wood anatomical traits. RNA sequencing of the developing xylem revealed that 1.5% of the analyzed genes were differentially expressed in response to drought, while 67% differed among the genotypes. Weighted gene correlation network analysis identified modules of co-expressed genes correlated with saccharification potential. These modules were enriched in gene ontology terms related to cell wall polysaccharide biosynthesis and modification and vesicle transport, but not to lignin biosynthesis. Among the most strongly saccharification-correlated genes, those with regulatory functions, especially kinases, were prominent. We further identified transcription factors whose transcript abundances differed among genotypes, and which were co-regulated with genes for biosynthesis and modifications of hemicelluloses and pectin. Overall, our study suggests that the regulation of pectin and hemicellulose metabolism is a promising target for improving wood quality of second generation bioenergy crops. The causal relationship of the identified genes and pathways with saccharification potential needs to be validated in further experiments.

Aim Mediterranean refugial areas are generally underrepresented in large-scale genetic surveys of forest trees. In the case of silver fir (Abies alba Mill.), this has led to divergent hypotheses about the exact location of glacial refugia and the trajectory of recolonization routes. Based on the comprehensive sampling of Apennine populations, we aimed to reconcile discrepancies about the number and location of refugia for silver fir in the Apennines and test alternative demographic scenarios developed from palaeobotanical and genetic data. Location Mediterranean Basin; the Apennines and surrounding areas. Methods 1167 individuals from 16 Apennine populations, extensively covering the species’ distribution along the Italian Peninsula, and eight populations from the Alps and Eastern Europe were genotyped at 16 nuclear and three chloroplast microsatellite markers. The geographical distribution of genetic variation was explored using Bayesian clustering and multivariate methods. Based on the inferred genetic structure, the demographic history of A. alba was assessed by the approximate Bayesian computation (ABC) analysis. Results Two unexpected characteristics of genetic structure emerged: a sharp genetic boundary in the central Apennines and a tight genetic connection between southern Apennine and Eastern European gene pools. Two Apennine areas, corresponding precisely with refugial areas hypothesized in most recent palaeobotanical syntheses, have high genetic diversity on a par with Eastern European populations. ABC analysis showed an ancient separation between Apennine and Eastern European gene pools followed by an admixture event that, mainly through directional gene flow via pollen, might have established the genetic similarity between southern Apennine and Eastern European populations. In addition, there was evidence that the central Apennines acted as a small-scale, isolated refugium during the Last Glacial Maximum. Main conclusions Silver fir rear edge populations have experienced a complex demographic history across several glacial-interglacial cycles, leading to unexpected genetic structure. Our study provides new insights into forest tree dynamics in the Mediterranean, showing the putative presence of multiple refugia for silver fir in the Apennines and a trans-Adriatic connection between silver fir populations in the southern Italy and the Balkans.

National audience

National audience

The evolutionary potential of long-lived species, such as forest trees, is fundamental for their local persistence under climate change (CC). Genome–environment association (GEA) analyses reveal if species in heterogeneous environments at the regional scale are under differential selection resulting in populations with potential preadaptation to CC within this area. In 79 natural [i]Fagus sylvatica[/i] populations, neutral genetic patterns were characterized using 12 simple sequence repeat (SSR) markers, and genomic variation (144 single nucleotide polymorphisms (SNPs) out of 52 candidate genes) was related to 87 environmental predictors in the latent factor mixed model, logistic regressions and isolation by distance/environmental (IBD/IBE) tests. SSR diversity revealed relatedness at up to 150m intertree distance but an absence of large-scale spatial genetic structure and IBE. In the GEA analyses, 16 SNPs in 10 genes responded to one or several environmental predictors and IBE, corrected for IBD, was confirmed. The GEA often reflected the proposed gene functions, including indications for adaptation to water availability and temperature. Genomic divergence and the lack of large-scale neutral genetic patterns suggest that gene flow allows the spread of advantageous alleles in adaptive genes. Thereby, adaptation processes are likely to take place in species occurring in heterogeneous environments, which might reduce their regional extinction risk under CC

The fate of peripheral forest tree populations is of particular interest in the context of climate change. These populations may concurrently be those where the most significant evolutionary changes will occur; those most facing increasing extinction risk; the source of migrants for the colonization of new areas at leading edges; or the source of genetic novelty for reinforcing standing genetic variation in various parts of the range. Deciding which strategy to implement for conserving and sustainably using the genetic resources of peripheral forest tree populations is a challenge. Here, we review the genetic and ecological processes acting on different types of peripheral populations and indicate why these processes may be of general interest for adapting forests and forest management to climate change. We particularly focus on peripheral populations at the rear edge of species distributions where environmental challenges are or will become most acute. We argue that peripheral forest tree populations are “natural laboratories” for resolving priority research questions such as how the complex interaction between demographic processes and natural selection shape local adaptation; and whether genetic adaptation will be sufficient to allow the long-term persistence of species within their current distribution. Peripheral populations are key assets for adaptive forestry which need specific measures for their preservation. The traditionally opposing views which may exist between conservation planning and sustainable forestry need to be reconciled and harmonized for managing peripheral populations. Based on existing knowledge, we suggest approaches and principles which may be used for the management and conservation of these distinctive and valuable populations, to maintain active genetic and ecological processes that have sustained them over time.

Highlight Osmotic stress rapidly induces strong transcriptome responses within the root apex and interferes with growth through a deep remodeling of hormonal status rather than by repressing the machinery of expansive growth., Molecular regulation of growth must include spatial and temporal coupling of cell production and cell expansion. The underlying mechanisms, especially under environmental challenge, remain obscure. Spatial patterns of cell processes make the root apex well suited to deciphering stress signaling pathways, and to investigating both processes. Kinematics and RNA-sequencing were used to analyze the immediate growth response of hydroponically grown Populus nigra cuttings submitted to osmotic stress. About 7400 genes and unannotated transcriptionally active regions were differentially expressed between the division and elongation zones. Following the onset of stress, growth decreased sharply, probably due to mechanical effects, before recovering partially. Stress impaired cell expansion over the apex, progressively shortened the elongation zone, and reduced the cell production rate. Changes in gene expression revealed that growth reduction was mediated by a shift in hormone homeostasis. Osmotic stress rapidly elicited auxin, ethylene, and abscisic acid. When growth restabilized, transcriptome remodeling became complex and zone specific, with the deployment of hormone signaling cascades, transcriptional regulators, and stress-responsive genes. Most transcriptional regulations fit growth reduction, but stress also promoted expression of some growth effectors, including aquaporins and expansins. Together, osmotic stress interfered with growth by activating regulatory proteins rather than by repressing the machinery of expansive growth.

Despite the large body of research devoted to understanding the role of Quaternary glacial cycles in the genetic divergence of European trees, the differential contribution of geographic isolation and/or environmental adaptation in creating population genetic divergence remains unexplored. In this study, we used a long-lived tree (Taxus baccata) as a model species to investigate the impact of Quaternary climatic changes on genetic diversity via neutral (isolation-by-distance) and selective (isolation-by-adaptation) processes. We applied approximate Bayesian computation to genetic data to infer its demographic history, and combined this information with past and present climatic data to assess the role of environment and geography in the observed patterns of genetic structure. We found evidence that yew colonized Europe from the East, and that European samples diverged into two groups (Western, Eastern) at the beginning of the Quaternary glaciations, c. 2.2 Myr before present. Apart from the expected effects of geographical isolation during glacials, we discovered a significant role of environmental adaptation during interglacials at the origin of genetic divergence between both groups. This process may be common in other organisms, providing new research lines to explore the effect of Quaternary climatic factors on present-day patterns of genetic diversity. © 2015 New Phytologist Trust.

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Understanding local adaptation in forest trees is currently a key research and societal priority. Geographically and ecologically marginal populations provide ideal case studies, because environmental stress along with reduced gene flow can facilitate the establishment of locally adapted populations. We sampled European silver fir (Abies alba Mill.) trees in the French Mediterranean Alps, along the margin of its distribution range, from pairs of high- and low-elevation plots on four different mountains situated along a 170-km east-west transect. The analysis of 267 SNP loci from 175 candidate genes suggested a neutral pattern of east-west isolation by distance among mountain sites. F(ST) outlier tests revealed 16 SNPs that showed patterns of divergent selection. Plot climate was characterized using both in situ measurements and gridded data that revealed marked differences between and within mountains with different trends depending on the season. Association between allelic frequencies and bioclimatic variables revealed eight genes that contained candidate SNPs, of which two were also detected using F(ST) outlier methods. All SNPs were associated with winter drought, and one of them showed strong evidence of selection with respect to elevation. Q(ST)-F(ST) tests for fitness-related traits measured in a common garden suggested adaptive divergence for the date of bud flush and for growth rate. Overall, our results suggest a complex adaptive picture for A. alba in the southern French Alps where, during the east-to-west Holocene recolonization, locally advantageous genetic variants established at both the landscape and local scales.

Chloroplast DNA polymorphism was analysed in forty-four Italian holm oak populations. Results obtained with different markers (PCR-RFLP and SSR) were congruent, showing a clear geographic structure of genetic diversity and high value of genetic differentiation (Gst = 0.80). By combining PCR-RFLP and SSR, eight haplotypes were identified in Italy, six of them in Sicily. Most populations were fixed for one haplotype. Some populations from the extreme West Mediterranean (Morocco) and the extreme East Mediterranean areas (Crete) were interpreted as reproductively isolated populations because they had completely different haplotypes. These results strongly support the hypothesis of glacial refugia existing in southern Italy, and underline the high conservation value of natural tree populations in Sicily, in which most diversity was detected., La Sicile, réservoir italien de la diversité de l'ADN chloroplastique de Quercus ilex L. Le polymorphisme de l'ADN chloroplastique a été analysé chez 44 populations italiennes de chêne vert. Les résultats obtenus avec différents marqueurs (PCR-RFLP et SSR) ont été cohérents, montrant clairement une structure géographique de la diversité génétique et une valeur élevée de la différentiation génétique (GST = 0,80). En combinant PCR-RFLP et SSR, huit haplotypes ont été identifiés en Italie dont six en Sicile. La plupart des populations ont été fixées par un haplotype. Des populations de l'extrême ouest méditerranéen (Maroc) et de l'extrême est (Crète) ont été interprétées comme des reproductions de populations isolées parce qu'elles ont des haplotypes différents. Ces résultats supportent fortement l'hypothèse d'un refuge glaciaire existant dans le Sud de l'Italie et soulignent la grande importance de la conservation des populations d'arbres en Sicile dans lesquelles une grande diversité a été détectée.

The recent advances in Next Generation Sequencing (NGS) technologies are accelerating the development of genomic resources and allowing a comparative understanding of the genome structure of forest trees. Sequencing a reduced snapshot of the genome is an alternative to the full genome sequencing, particularly interesting for non-model conifer tree species where full sequencing is still hardly feasible. In the framework of NGS, we applied two genome complexity reduction methods: mRNAseq and RADseq (Restriction site Associated DNA sequencing) in a Pinaceae species with a challenging large and complex genome that has hindered the development of molecular markers so far: [i]Cedrus atlantica[/i] Manetti. This study was a first tentative of applying RADseq in a coniferous tree. The PstIhypomethylation sensitive enzyme was used. Sequence similarity and functional annotation analyses showed comparable redundancy proportions and coding-like sequences fractions between the mRNAseq and RADseq assemblies. It gave insights about the methylation profile and confirmed the ability of the RADseq to generate a redundancy-reduced filtrate of the genome, enriched by coding sequences in conifers. RADseq generated thousands of Single Nucleotide Polymorphism (SNP) markers from which we selected a high-quality subgroup and evaluated the ascertainment bias due to our choice criteria.

International audience; The availability of high-resolution, cost-effective polymorphic genetic markers displaying Mendelian inheritance is a prerequisite for fine-scale population genetic analyses as well as informed conservation and sustainable management. Silver fir (Abies alba Mill.) is a widespread European species of economic and ecological importance for which genetic markers are needed but difficult to develop, as in most conifer species. In this work, we introduce two sets of new multiplexed transcriptome-derived expressed sequence tag microsatellites (EST-simple sequence repeats (SSRs)) which we compare to a set of multiplexed genomic microsatellites (gSSRs). For both marker types, transferability was tested in 17 congeneric taxa. A total of 16 new EST-SSRs and two new gSSRs were developed. The EST-SSR multiplexes produced easily scorable amplification patterns that allow rapid and cost-effective genotyping at low-error rates, and include loci that display very low null allele frequencies. Generally, EST-SSRs displayed lower polymorphism and frequency of null alleles, but higher genetic differentiation among populations than gSSRs. Preliminary tests revealed that the EST-SSR markers are highly transferable and polymorphic across Abies species. This study also confirmed that SSRs can be successfully developed using next-generation sequencing technology also in large genome species such as conifers.

Aleppo pine (Pinus halepensis Mill.) is a relevant conifer species for studying adaptive responses to drought and fire regimes in the Mediterranean region. In this study, we performed Illumina next-generation sequencing of two phenotypically divergent Aleppo pine accessions with the aims of (i) characterizing the transcriptome through Illumina RNA-Seq on trees phenotypically divergent for adaptive traits linked to fire adaptation and drought, (ii) performing a functional annotation of the assembled transcriptome, (iii) identifying genes with accelerated evolutionary rates, (iv) studying the expression levels of the annotated genes and (v) developing gene-based markers for population genomic and association genetic studies. The assembled transcriptome consisted of 48 629 contigs and covered about 54.6 Mbp. The comparison of Aleppo pine transcripts to Picea sitchensis protein-coding sequences resulted in the detection of 34 014 SNPs across species, with a Ka/Ks average value of 0.216, suggesting that the majority of the assembled genes are under negative selection. Several genes were differentially expressed across the two pine accessions with contrasted phenotypes, including a glutathione-s-transferase, a cellulose synthase and a cobra-like protein. A large number of new markers (3334 amplifiable SSRs and 28 236 SNPs) have been identified which should facilitate future population genomics and association genetics in this species. A 384-SNP Oligo Pool Assay for genotyping with the Illumina VeraCode technology has been designed which showed an high overall SNP conversion rate (76.6%). Our results showed that Illumina next-generation sequencing is a valuable technology to obtain an extensive overview on whole transcriptomes of nonmodel species with large genomes. © 2014 John Wiley & Sons Ltd., This research was funded by the Spanish National Research Plan (VaMPiro, CGL2008-05289-C02-01/02, TrEvol, CGL2012- 39938-C02-01, and AdapCon, CGL2011-30182-C02-01), and the ERA-Net BiodivERsA (LinkTree project, EUI2008-03713), which included the Spanish Ministry of Economy and Competitiveness as national funder (part of the 2008 BiodivERsA call for research proposals). SP and GGV were also supported by a grant of the Italian Ministry of Education and Scientific Research (‘Biodiversitalia’, RBAP10A2T4). DG acknowledges the support of the Spanish Ministry of Economy and Competiveness through a ‘Ramon y Cajal’ fellowship and SCGM the support of a Senior Marie Curie Intra European Fellowship within the 7th European Community Framework Programme (PIEF-GA-2012-328146).

International audience

[b]Aim[/b][br/] Many tropical tree species have poorly delimited taxonomic boundaries and contain undescribed or cryptic species. We examined the genetic structure of a species complex in the tree genus Carapa in the Neotropics in order to evaluate age, geographic patterns of diversity and evolutionary relationships, and to quantify levels of introgression among currently recognized species.[br/] [br/] [b]Location[/b][br/] Lowland moist forests in the Guiana Shield, the Central and Western Amazon Basin, Chocó and Central America.[br/] [br/] [b]Methods[/b][br/] Genetic structure was analysed using seven nuclear simple sequence repeats (nuSSR), five chloroplast SSRs (cpSSR), and two chloroplast DNA (cpDNA) intergenic sequences (trnH-psbA and trnC-ycf6). Bayesian clustering analysis of the SSR data was used to infer population genetic structure and to assign 324 samples to their most likely genetic cluster. Bayesian coalescence analyses were performed on the two cpDNA markers to estimate evolutionary relationships and divergence times.[br/] [br/] [b]Results[/b][br/] Two genetic clusters (nu_guianensis and nu_surinamensis) were detected, which correspond to the Neotropical species C. guianensis (sensu latu) and C. surinamensis. Fourteen cpDNA haplotypes clustered into six haplogroups distributed between the two nuclear genetic clusters. Divergence between the haplogroups was initiated in the Miocene, with some haplotype structure evolving as recently as the Pleistocene. The absence of complete lineage sorting between the nuclear and chloroplast genomes and the presence of hybrid individuals suggest that interspecific reproductive barriers are incomplete. NuSSR diversity was highest in C. guianensis and, within C. guianensis, cpDNA diversity was highest in the Central and Western Amazon Basin. Regional genetic differentiation was strong but did not conform to an isolation-by-distance process or exhibit a phylogeographical signal.[br/] [br/] [b]Main conclusions[/b][br/] The biogeographical history of Neotropical Carapa appears to have been influenced by events that took place during the Neogene. Our results point to an Amazonian centre of origin and diversification of Neotropical Carapa, with subsequent migration to the Pacific coast of South America and Central America. Gene flow apparently occurs among species, and introgression events are supported by inconsistencies between chloroplast and nuclear lineage sorting. The absence of phylogeographical structure may be a result of the ineffectiveness of geographical barriers among populations and of reproductive isolation mechanisms among incipient and cryptic species in this species complex.

[b]Aim[/b][br/] [br/] The phylogeographical history of Neotropical species can be difficult to reconstruct because of superimposed Neogene and Quaternary histories, and because of taxonomic uncertainty. We analysed range-wide genetic diversity in a widespread pioneer tree species, Jacaranda copaia (Aubl.) D. Don, to characterize phylogeographical structure, date the evolutionary relationships among lineages, and evaluate the role of dispersal and vicariance in establishing the present geographical range.[br/] [br/] [br/] [b]Location[/b][br/] [br/] Guiana Shield; central, southern and western Amazon Basin; Chocó region; Central America.[br/] [br/] [br/] [b]Methods[/b][br/] [br/] We analysed nine nuclear simple sequence repeat loci (nuSSR), eight chloroplast SSRs (cpSSR), and two cpDNA intergenic sequences in 341 adult trees. Genetic differentiation at nuSSRs was inferred using Bayesian clustering. Dating of chloroplast lineage divergence was obtained using a range of published mutation rates and Bayesian coalescence analyses. Population divergence dating was performed using an isolation-with-migration model for eight loci (one cp sequence and seven nuSSRs).[br/] [br/] [br/] [b]Results[/b][br/] [br/] Nuclear SSR variation identified three geographically overlapping clusters (nu-1, nu-2, nu-3). Twelve cpDNA haplotypes were clustered into two haplogroups (cp-1, cp-2) with the central Amazon harbouring the highest diversity. Molecular dating analysis suggests that cpDNA haplotype diversification started around the end of the Pliocene (2.61 Ma on average), whereas population divergence was more recent and occurred during the mid-Quaternary (point estimates between 357 and 436 ka).[br/] [br/] [br/] [b]Main conclusions[/b][br/] [br/] The genetic variation of J. copaia in the Neotropics was shaped mainly by Pleistocene events. Chloroplast diversity did not display the expected cis/trans Andean disjunction, indicating recent dispersal. Nuclear variation revealed that separate regions share a recent history, with a centre of diversity in the central Amazon Basin. The geographical pattern of diversity is congruent with the distribution of the two subspecies, J. copaia copaia and J. copaia spectabilis, and evidence of nuSSR admixture between the two taxa supports their classification as subspecies.

Y a-t-il vraiment eu en France une degradation de la valeur travail ? Les jeunes sont-ils aujourd’hui moins bien disposes a l’egard du travail que les autres tranches d’âge ? Qu’en est-il du rapport au travail des differentes generations, des hommes et des femmes, des Francais et des Europeens ? Cet ouvrage propose a la fois une histoire longue de notre rapport au travail – une histoire de sa signification et de sa valorisation - et un voyage dans la diversite et les transformations des rapports au travail. A l’aide des donnees issues des enquetes europeennes et d’entretiens realises en face a face en Europe, il montre la transformation des attentes que les individus placent sur le travail – des attentes de plus en plus expressives, l’espoir d’obtenir du travail un possible epanouissement – et la contradiction de plus en plus vive, en France comme en Europe, entre ces attentes et les changements en cours dans les conditions concretes d’exercice du travail et de l’emploi. L’ouvrage s’interroge sur la possibilite de reconcilier l’ethos contemporain du travail, porte notamment par les femmes et les jeunes – une conception polycentree de l’activite - , et des organisations de plus en plus soumises aux imperatifs de rentabilite et de productivite, en proposant un projet europeen fonde sur la qualite de l’emploi.

International audience

National audience

International audience; This paper presents a new routing protocol for Delay Tolerant Networks (DTNs), based on a distributed swarm intelligence approach. The protocol is called Cultural Greedy Ant (CGrAnt), as it uses a Cultural Algorithm (CA) and a greedy version of the Ant Colony Optimization (ACO) metaheuristic. The term greedy implies the use of a deterministic transition rule to exploit previously found good paths or explore new paths by selecting, from among a set of candidates, the most promising message forwarders. CGrAnt chooses each next node toward the message destination based on pheromone concentration (i.e., global information) whenever it is available. However, as the pheromone is not always available due to connectivity partitions, local information (i.e., heuristic function) captured from DTN nodes also supports a routing decision. Specific metrics and information gathered from the evolution are stored in Situational, Domain, and Historical Knowledge. The knowledge composes the CA's belief space, which is used to guide and improve the search. CGrAnt is compared with two DTN routing protocols (Epidemic and PROPHET) in an activity-based scenario. The results show that CGrAnt achieves a higher delivery ratio and lower byte redundancy than Epidemic and PROPHET.

National audience; Un enjeu majeur de la génétique évolutive est de comprendre comment l’adaptation locale se développe en population naturelle, et comment les différentes forces évolutives y contribuent. Les études expérimentales d’adaptation locale utilisent couramment les gradients altitudinaux présentant une variation spatiale marquée des conditions environnementales. Dans ces conditions, on s’attend à ce que la différentiation génétique pour les caractères (traditionnellement mesurée par QST) et pour les gènes déterminant ces caractères (traditionnellement mesurée par FSTq) le long du gradient soit gouvernée de façon prédominante par la sélection et les flux de gènes, et peu influencée en revanche par la dérive génétique et la mutation. En particulier, des études théoriques ont montré un découplage entre QST et FST lorsque que les flux de gènes sont forts et/ou que la sélection est récente. Dans cette étude, nous avons testé cette hypothèse en combinant une approche de génomique expérimentale et des simulations dans des populations naturelles de hêtre commun (F. sylvatica) séparées de ~trois kilomètres et soumis à des environnements contrastés. Pour l’approche expérimentale, nous avons échantillonné 4 populations sur deux gradients altitudinaux sur le Mont Ventoux (avec une population à haute altitude et une à basse altitude sur chaque gradient). Cinquante-huit gènes potentiellement impliqués dans la réponse aux stress abiotiques et dans le débourrement ont été séquencés sur un total de quatre-vingt-seize individus, révélant 581 SNPs (Single Nucleotide Polymorphisms). Différentes approches ont été utilisées pour identifier les SNP outlier, présentant une différentiation plus forte qu’attendu sous un modèle neutre sans sélection. Un total de 13 SNPs outlier a été identifié; en particulier un gène codant pour une pectin methylesterase apparaît outlier sur les deux gradients étudiés. Par ailleurs, nous avons utilisé un modèle mécaniste individu-centré pour simuler les patrons de diversité phénotypique et génétique attendus le long du gradient pour la phénologie du débourrement végétatif, un caractère généralement adaptatif dans la réponse aux variations de température. Les résultats des simulations confirment que la différentiation génétique observée pour le caractère (QST) est généralement plus forte que celle observée au gène (FSTq), et montrent en outre que les patrons de différentiation le long du gradient sont généralement non monotones.

The study of the dispersal capability of a species can provide essential information for the management and conservation of its genetic variability. Comparison of gene flow rates among populations characterized by different management and evolutionary histories allows one to decipher the role of factors such as isolation and tree density on gene movements. We used two paternity analysis approaches and different strategies to handle the possible presence of genotyping errors to obtain robust estimates of pollen flow in four European beech (Fagus sylvatica L.) populations from Austria and France. In each country one of the two plots is located in an unmanaged forest; the other plots are managed with a shelterwood system and inside a colonization area (in Austria and France, respectively). The two paternity analysis approaches provided almost identical estimates of gene flow. In general, we found high pollen immigration (~75% of pollen from outside), with the exception of the plot from a highly isolated forest remnant (~50%). In the two unmanaged plots, the average within-population pollen dispersal distances (from 80 to 184 m) were higher than previously estimated for beech. From the comparison between the Austrian managed and unmanaged plots, that are only 500 m apart, we found no evidence that either gene flow or reproductive success distributions were significantly altered by forest management. The investigated phenotypic traits (crown area, height, diameter and flowering phenology) were not significantly related with male reproductive success. Shelterwood seems to have an effect on the distribution of within-population pollen dispersal distances. In the managed plot, pollen dispersal distances were shorter, possibly because adult tree density is three-fold (163 versus 57 trees per hectare) with respect to the unmanaged one. © 2012 Macmillan Publishers Limited All rights reserved.

International audience; PREMISE OF THE STUDY: To study the genetic structure among three morphotypes of an African rainforest tree species, Santiria trimera, nuclear microsatellite markers were isolated and characterized. METHODS AND RESULTS: Seven polymorphic loci were isolated using a pyrosequencing-based protocol and successfully amplified on three different morphotypes of S. trimera. For six of the seven loci, there is at least one private allele for one of the three morphotypes. The mean effective number of alleles is about four for each of the three morphotypes. CONCLUSIONS: These microsatellite markers are promising to explore the genetic delimitation among sympatric morphotypes found in Gabonese forests and to study the spatial genetic structure within each gene pool.

Background Genetic markers and linkage mapping are basic prerequisites for comparative genetic analyses, QTL detection and map-based cloning. A large number of mapping populations have been developed for oak, but few gene-based markers are available for constructing integrated genetic linkage maps and comparing gene order and QTL location across related species. Results We developed a set of 573 expressed sequence tag-derived simple sequence repeats (EST-SSRs) and located 397 markers (EST-SSRs and genomic SSRs) on the 12 oak chromosomes (2n = 2x = 24) on the basis of Mendelian segregation patterns in 5 full-sib mapping pedigrees of two species: Quercus robur (pedunculate oak) and Quercus petraea (sessile oak). Consensus maps for the two species were constructed and aligned. They showed a high degree of macrosynteny between these two sympatric European oaks. We assessed the transferability of EST-SSRs to other Fagaceae genera and a subset of these markers was mapped in Castanea sativa, the European chestnut. Reasonably high levels of macrosynteny were observed between oak and chestnut. We also obtained diversity statistics for a subset of EST-SSRs, to support further population genetic analyses with gene-based markers. Finally, based on the orthologous relationships between the oak, Arabidopsis, grape, poplar, Medicago, and soybean genomes and the paralogous relationships between the 12 oak chromosomes, we propose an evolutionary scenario of the 12 oak chromosomes from the eudicot ancestral karyotype. Conclusions This study provides map locations for a large set of EST-SSRs in two oak species of recognized biological importance in natural ecosystems. This first step toward the construction of a gene-based linkage map will facilitate the assignment of future genome scaffolds to pseudo-chromosomes. This study also provides an indication of the potential utility of new gene-based markers for population genetics and comparative mapping within and beyond the Fagaceae.

This paper proposes a new prediction-based routing protocol for Delay Tolerant Networks (DTNs) called Greedy Ant (GrAnt). GrAnt uses a greedy transition rule of the Ant Colony Optimization (ACO) metaheuristic to provide the exploitation of good previous solutions, when available, and to forward the messages to the most promising node(s). By making use of pheromone concentration and heuristic function, GrAnt protocol provides three modules: scheduling, routing, and buffer management. Simulation results show that in a community-based movement model GrAnt is able to achieve higher successfully message delivery and lower bytes overhead than Epidemic and PROPHET. In a buffer size of 5 MB, for example, GrAnt delivers almost 79 percent of the messages against 39 percent of messages delivered by PROPHET and 45 percent of messages delivered by Epidemic.