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Sökning: WFRF:(Berlin Sofia)

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1.
  • Zwedberg, Sofia, et al. (författare)
  • Midwives' experiences as preceptors and the development of good preceptorships in obstetric units
  • 2020
  • Ingår i: Midwifery. - : ELSEVIER SCI LTD. - 0266-6138 .- 1532-3099. ; 87
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To study midwives' experience in their role as a preceptor and their perception on how to best support midwifery students in obstetrics units. Obstetric units are an important learning area for student midwives but knowledge on how to become a good midwife preceptor is limited. Design: This qualitative study explores midwife preceptors' experience of supervising midwifery students in three obstetric units in Sweden. Following ethical approval seventeen midwife preceptors were inter- viewed and data were analysed thematically. Findings: Thematic analysis of the interviews resulted in the identification of two themes and five sub- themes: (1) self-efficacy in the preceptor role which involves (a) being confident in the professional posi- tion and (b) having the support of management and colleagues and (2) supporting the student to attain self-confidence and independence which entails (a) helping the student to grow, (b) facilitating reflection in learning situations, and (c) "taking a step back". Key conclusion: Good preceptorship occurs when midwives achieve full self-efficacy, when they master the preceptor role, and when they have enhanced their abilities to help, the student reach confidence and independence. Implications for practice: Health care organisations needs to develop and support midwifery preceptor- ships
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2.
  • Berlin Kolm, Sofia, et al. (författare)
  • High-density linkage mapping and evolution of paralogs and orthologs in Salix and Populus
  • 2010
  • Ingår i: BMC Genomics. - : BioMed Central. - 1471-2164. ; 11
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Salix (willow) and Populus (poplar) are members of the Salicaceae family and they share many ecological as well as genetic and genomic characteristics. The interest of using willow for biomass production is growing, which has resulted in increased pressure on breeding of high yielding and resistant clones adapted to different environments. The main purpose of this work was to develop dense genetic linkage maps for mapping of traits related to yield and resistance in willow. We used the Populus trichocarpa genome to extract evenly spaced markers and mapped the orthologous loci in the willow genome. The marker positions in the two genomes were used to study genome evolution since the divergence of the two lineages some 45 mya.Results: We constructed two linkage maps covering the 19 linkage groups in willow. The most detailed consensus map, S(1), contains 495 markers with a total genetic distance of 2477 cM and an average distance of 5.0 cM between the markers. The S(3) consensus map contains 221 markers and has a total genetic distance of 1793 cM and an average distance of 8.1 cM between the markers. We found high degree of synteny and gene order conservation between willow and poplar. There is however evidence for two major interchromosomal rearrangements involving poplar LG I and XVI and willow LG Ib, suggesting a fission or a fusion in one of the lineages, as well as five intrachromosomal inversions. The number of silent substitutions were three times lower (median: 0.12) between orthologs than between paralogs (median: 0.37-0.41).Conclusions: The relatively slow rates of genomic change between willow and poplar mean that the genomic resources in poplar will be most useful in genomic research in willow, such as identifying genes underlying QTLs of important traits. Our data suggest that the whole-genome duplication occurred long before the divergence of the two genera, events which have until now been regarded as contemporary. Estimated silent substitution rates were 1.28 x 10(-9) and 1.68 x 10(-9) per site and year, which are close to rates found in other perennials but much lower than rates in annuals.
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3.
  • Darolti, Iulia, et al. (författare)
  • Slow evolution of sex-biased genes in the reproductive tissue of the dioecious plant Salix viminalis
  • 2018
  • Ingår i: Molecular Ecology. - : WILEY. - 0962-1083 .- 1365-294X. ; 27:3, s. 694-708
  • Tidskriftsartikel (refereegranskat)abstract
    • The relative rate of evolution for sex-biased genes has often been used as a measure of the strength of sex-specific selection. In contrast to studies in a wide variety of animals, far less is known about the molecular evolution of sex-biased genes in plants, particularly in dioecious angiosperms. Here, we investigate the gene expression patterns and evolution of sex-biased genes in the dioecious plant Salix viminalis. We observe lower rates of sequence evolution for male-biased genes expressed in the reproductive tissue compared to unbiased and female-biased genes. These results could be partially explained by the lower codon usage bias for male-biased genes leading to elevated rates of synonymous substitutions compared to unbiased genes. However, the stronger haploid selection in the reproductive tissue of plants, together with pollen competition, would also lead to higher levels of purifying selection acting to remove deleterious variation. Future work should focus on the differential evolution of haploid- and diploid-specific genes to understand the selective dynamics acting on these loci.
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4.
  • Fogelqvist, Johan, et al. (författare)
  • Genetic and morphological evidence for introgression between three species of willows
  • 2015
  • Ingår i: BMC Evolutionary Biology. - : BioMed Central. - 1471-2148. ; 15
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Hybridization and introgression are said to occur relatively frequently in plants, and in particular among different species of willows. However, data on the actual frequency of natural hybridization and introgression is rare. Here, we report the first fine-scale genetic analysis of a contact zone shared between the three basket willow species, Salix dasyclados, S. schwerinii and S. viminalis in the vicinity of the Lake Baikal in Southern Siberia. Individuals were sampled in fourteen populations and classified as pure species or hybrids based on a set of morphological characters. They were then genotyped at 384 nuclear SNP and four chloroplast SSR loci. The STRUCTURE and NewHybrids softwares were used to estimate the frequency and direction of hybridization using genotypic data at the nuclear SNP loci.Results: As many as 19 % of the genotyped individuals were classified as introgressed individuals and these were mainly encountered in the centre of the contact zone. All introgressed individuals were backcrosses to S. viminalis or S. schwerinii and no F1 or F2 hybrids were found. The rest of the genotyped individuals were classified as pure species and formed two clusters, one with S. schwerinii individuals and the other with S. viminalis and S. dasyclados individuals. The two clusters were significantly genetically differentiated, with F-ST = 0.333 (0.282-0.382, p < 0.001). In contrast, for the chloroplast haplotypes, no genetic differentiation was observed as they were completely shared between the species. Based on morphological classification only 5 % of the individuals were classified as introgressed individuals, which was much less than what was detected using genotypic data.Conclusions: We have discovered a new willow hybrid zone with relatively high frequency of introgressed individuals. The low frequency of F1 hybrids indicates that ongoing hybridization is limited, which could be because of the presence of reproductive barriers or simply because the conditions are not favorable for hybridization. We further conclude that in order to get a complete picture of the species composition of a hybrid zone it is necessary to use a combination of morphological characters and genetic data from both nuclear and chloroplast markers.
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5.
  • Ghelardini, Luisa, et al. (författare)
  • Genetic architecture of spring and autumn phenology in Salix
  • 2014
  • Ingår i: BMC Plant Biology. - : BioMed Central. - 1471-2229. ; 14
  • Tidskriftsartikel (refereegranskat)abstract
    • Background  In woody plants from temperate regions, adaptation to the local climate results in annual cycles of growth and dormancy, and optimal regulation of these cycles are critical for growth, long-term survival, and competitive success. In this study we have investigated the genetic background to growth phenology in a Salix pedigree by assessing genetic and phenotypic variation in growth cessation, leaf senescence and bud burst in different years and environments. A previously constructed linkage map using the same pedigree and anchored to the annotated genome of P. trichocarpa was improved in target regions and used for QTL analysis of the traits. The major aims in this study were to map QTLs for phenology traits in Salix, and to identify candidate genes in QTL hot spots through comparative mapping with the closely related Populus trichocarpa.  Results  All traits varied significantly among genotypes and the broad-sense heritabilities ranged between 0.5 and 0.9, with the highest for leaf senescence. In total across experiment and years, 80 QTLs were detected. For individual traits, the QTLs explained together from 21.5 to 56.5% of the variation. Generally each individual QTL explained a low amount of the variation but three QTLs explained above 15% of the variation with one QTL for leaf senescence explaining 34% of the variation. The majority of the QTLs were recurrently identified across traits, years and environments. Two hotspots were identified on linkage group (LG) II and X where narrow QTLs for all traits co-localized.  Conclusions  This study provides the most detailed analysis of QTL detection for phenology in Salix conducted so far. Several hotspot regions were found where QTLs for different traits and QTLs for the same trait but identified during different years co-localised. Many QTLs co-localised with QTLs found in poplar for similar traits that could indicate common pathways for these traits in Salicaceae. This study is an important first step in identifying QTLs and candidate genes for phenology traits in Salix.
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6.
  • Hallingback, Henrik R., et al. (författare)
  • Association mapping in Salix viminalis L. (Salicaceae) - identification of candidate genes associated with growth and phenology
  • 2016
  • Ingår i: Global Change Biology Bioenergy. - : Wiley Open Access. - 1757-1693 .- 1757-1707. ; 8:3, s. 670-685
  • Tidskriftsartikel (refereegranskat)abstract
    • Willow species (Salix) are important as short-rotation biomass crops for bioenergy, which creates a demand for faster genetic improvement and breeding through deployment of molecular marker-assisted selection (MAS). To find markers associated with important adaptive traits, such as growth and phenology, for use in MAS, we genetically dissected the trait variation of a Salix viminalis (L.) population of 323 accessions. The accessions were sampled throughout northern Europe and were established at two field sites in Pustnas, Sweden, and at Woburn, UK, offering the opportunity to assess the impact of genotype-by-environment interactions (GxE) on trait-marker associations. Field measurements were recorded for growth and phenology traits. The accessions were genotyped using 1536 SNP markers developed from phenology candidate genes and from genes previously observed to be differentially expressed in contrasting environments. Association mapping between 1233 of these SNPs and the measured traits was performed taking into account population structure and threshold selection bias. At a false discovery rate (FDR) of 0.2, 29 SNPs were associated with bud burst, leaf senescence, number of shoots or shoot diameter. The percentage of accession variation explained by these associations ranged from 0.3% to 4.4%, suggesting that the studied traits are controlled by many loci of limited individual impact. Despite this, a SNP in the EARLY FLOWERING 3 gene was repeatedly associated (FDR<0.2) with bud burst. The rare homozygous genotype exhibited 0.4-1.0 lower bud burst scores than the other genotype classes on a five-grade scale. Consequently, this marker could be promising for use in MAS and the gene deserves further study. Otherwise, associations were less consistent across sites, likely due to their small estimates and to considerable GxE interactions indicated by multivariate association analyses and modest trait accession correlations across sites (0.32-0.61).
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7.
  • Pucholt, Pascal, et al. (författare)
  • Genome-wide transcriptional and physiological responses to drought stress in leaves and roots of two willow genotypes
  • 2015
  • Ingår i: BMC Plant Biology. - : BioMed Central. - 1471-2229 .- 1471-2229. ; 15
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Drought is a major environmental stress that can have severe impacts on plant productivity and survival. Understanding molecular mechanisms of drought responses is crucial in order to breed for drought adapted plant cultivars. The aim of the present study was to investigate phenotypic and transcriptional drought responses in two willow genotypes (520 and 592) originating from an experimental cross between S. viminalis x (S. viminalis x S. schwerinii). Willows are woody perennials in the Salicaceae plant family that are grown as bioenergy crops worldwide. Methods: An experiment was conducted where plants were exposed to drought and different eco-physiological parameters were assessed. RNA-seq data was furthermore generated with the Illumina technology from root tips and leaves from plants grown in drought and well-watered (WW) conditions. The RNA-seq data was assembled de novo with the Trinity assembler to create a reference gene set to which the reads were mapped in order to obtain differentially expressed genes (DEGs) between the drought and WW conditions. To investigate molecular mechanisms involved in the drought response, GO enrichment analyses were conducted. Candidate genes with a putative function in the drought response were also identified. Results: A total of 52,599 gene models were obtained and after filtering on gene expression (FPKM >= 1), 35,733 gene models remained, of which 24,421 contained open reading frames. A total of 5,112 unique DEGs were identified between drought and WW conditions, of which the majority were found in the root tips. Phenotypically, genotype 592 displayed less growth reduction in response to drought compared to genotype 520. At the transcriptional level, genotype 520 displayed a greater response in the leaves as more DEGs were found in genotype 520 compared to genotype 592. In contrast, the transcriptional responses in the root tips were rather similar between the two genotypes. A core set of candidate genes encoding proteins with a putative function in drought response was identified, for example MYBs and bZIPs as well as chlorophyll a/b binding proteins. Discussion: We found substantial differences in drought responses between the genotypes, both at the phenotypic and transcriptional levels. In addition to the genotypic variation in several traits, we also found indications for genotypic variation in trait plasticity, which could play a role in drought adaptation. Furthermore, the two genotypes displayed overall similar transcriptional responses in the root tips, but more variation in the leaves. It is thus possible that the observed phenotypic differences could be a result of transcriptional differences mostly at the leaf level. Conclusions: This study has contributed to a better general understanding of drought responses in woody plants, specifically in willows, and has implications for breeding research towards more drought adapted plants.
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8.
  • Quintela, Maria, et al. (författare)
  • Genetic diversity and differentiation among Lagopus lagopus populations in Scandinavia and Scotland : evolutionary significant units confirmed by SNP markers
  • 2010
  • Ingår i: Molecular Ecology. - : Wiley: 12 months. - 0962-1083 .- 1365-294X. ; 19:12, s. 2380-2393
  • Tidskriftsartikel (refereegranskat)abstract
    • Single Nucleotide Polymorphism in four Scandinavian populations of willow grouse (Lagopus lagopus) and two Scottish populations of red grouse (Lagopus lagopus scoticus) were assessed at 13 protein-coding loci. We found high levels of diversity, with one substitution every 55 bp as an average and a total of 76 unlinked parsimony informative SNPs. Different estimators of genetic diversity such as: number of synonymous and non-synonymous sites, average number of alleles, number and percentage of polymorphic loci, mean nucleotide diversity (pi(s), pi(a)) and gene diversity at synonymous and non-synonymous sites showed higher diversity in the northern populations compared to southern ones. Strong levels of purifying selection found in all the populations together with neutrality tests conforming to neutral expectations agree with large effective population sizes. Assignment tests reported a clear distinction between Scandinavian and Scottish grouse suggesting the existence of two different evolutionary significant units. The divergence time between willow and red grouse ranging between 12 500 and 125 000 years, in conjunction with the presence of 'specific' markers for each subspecies prompt a reassessment of the taxonomical status of the Scottish red grouse.
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9.
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10.
  • Berlin, S., et al. (författare)
  • Genetic diversity, population structure and phenotypic variation in European Salix viminalis L. (Salicaceae)
  • 2014
  • Ingår i: Tree Genetics & Genomes. - : Springer Verlag (Germany). - 1614-2942 .- 1614-2950. ; 10:6, s. 1595-1610
  • Tidskriftsartikel (refereegranskat)abstract
    • To investigate the potential of association genetics for willow breeding, Salix viminalis germplasm was assembled from UK and Swedish collections (comprising accessions from several European countries) and new samples collected from nature. A subset of the germplasm was planted at two sites (UK and Sweden), genotyped using 38 SSR markers and assessed for phenological and biomass traits. Population structure, genetic differentiation (F-ST) and quantitative trait differentiation (Q(ST)) were investigated. The extent and patterns of trait adaptation were assessed by comparing F-ST and Q(ST) parameters. Of the 505 genotyped diploid accessions, 27 % were not unique. Genetic diversity was high: 471 alleles was amplified; the mean number of alleles per locus was 13.46, mean observed heterozygosity was 0.55 and mean expected heterozygosity was 0.62. Bayesian clustering identified four subpopulations which generally corresponded to Western Russia, Western Europe, Eastern Europe and Sweden. All pairwise F-ST values were highly significant (p<0.001) with the greatest genetic differentiation detected between the Western Russian and the Western European subpopulations (F-ST = 0.12), and the smallest between the Swedish and Eastern European populations (F-ST = 0.04). The Swedish population also had the highest number of identical accessions, supporting the view that S. viminalis was introduced into this country and has been heavily influenced by humans. Q(ST) values were high for growth cessation and leaf senescence, and to some extent stem diameter, but low for bud burst time and shoot number. Overall negative clines between longitudinal coordinates and leaf senescence, bud burst and stem diameter were also found.
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