24 research outputs found
Archived Data - Genetic breaks caused by ancient forest fragmentation: phylogeography of Staudtia kamerunensis (Myristicaceae) reveals distinct clusters in the Congo Basin
No full textList of the 400 genotyped Staudtia kamerunensis accessions from Central Africa included in Vanden Abeele & Matvijev et al. 2023 - Tree Genetics & Genomes, and the corresponding alleles for each of the 14 microsatellite markers (0-0 indicates missing alleles
Ohio impromptu, genre and Beckett on film
No full textSamuel Beckett’s choice of the title Ohio Impromptu to name the play first performed to an audience of academics and scholars at Columbus Ohio in 1981 is one manifestation of its author’s interest in the question of literary genre; more generally, in Beckett’s dramatic works one encounters a meticulous attention to the activity of categorisation, even if the energy is often directed toward the creation of phantom genres for spectral exemplars. This essay concerns itself with Ohio Impromptu in particular because by means of elements specific to this play (including the context in which it was first performed) it comments upon its own very failure to occupy its designated genre co-ordinates (these include its identity both as a play and as an ‘impromptu’). This play, which is so apt to incorporate other genres, however, is presided over by a stage direction which locates it firmly in the theatrical context. It is in its deliberate failure to attend to this stage direction that the Beckett on Film version of the play goes beyond the mere treacherous fidelity that is inevitably a feature of any adaptation. In arguing this, the essay analyses the foregrounding in the play of questions that can be said to pertain to genre (in several senses). Its more specific intention is to suggest that, via a combination of casting and special effects, the adaptation succeeds not only in cancelling the critical reflection on the ‘genre gesture’ that is lodged in Ohio Impromptu, but also in eradicating the very disjunction between Reader and Listener upon which the play depends
Comparative phylogeography of widespread tree species from the Congo Basin
No full textThe aim of this PhD study was to gain new insights into the evolutionary history of the Central African rainforests, which are among the most complex and diverse ecosystems on earth. Even today, many questions regarding the underlying dynamics and evolutionary processes shaping that remarkable diversity remain unanswered, since relatively few studies have focused on the vast tropical forests growing in the Congo Basin. Therefore, we applied various molecular approaches to study the levels of genetic diversity and patterns of differentiation within and between population of the tropical tree species Scorodophloeus zenkeri, Staudtia kamerunensis and Prioria balsamifera. In Chapter 2, we conducted a phylogeographic study on the widespread tropical tree Scorodophloeus zenkeri to assess the impact of past forest fragmentation in Central African lowland forests. By applying Bayesian clustering methods, we revealed six intraspecific genetic clusters within the species. The observed genetic discontinuities most likely result from forest fragmentation during the glacial periods of the Pleistocene. Populations in Lower Guinea appeared differentiated from those in Congolia, and both bioregions harboured distinct genetic clusters.In Chapter 3, we developed 16 highly polymorphic microsatellite primers (SSRs) for Staudtia kamerunensis, a timber species for which species-specific genetic markers were lacking. By validating the developed markers in three populations, we demonstrated their usefulness to study gene flow, population structure and spatial distribution of genetic diversity in S. kamerunensis.In Chapter 4, we applied the newly developed SSRs, two nuclear gene markers and a chloroplast marker to search for evolutionary lineages in Staudtia kamerunensis, a species with a complex taxonomical history. Our analyses reveal multiple genetic discontinuities among populations throughout Central Africa, probably resulting from ancient rainforest fragmentation during cold and dry periods in the Pliocene and/or Pleistocene. However, the clear genetic disjunction observed between northern and southern populations in Lower Guinea could correspond to a genetic break between the kamerunensis and gabonensis varieties described in Staudtia kamerunensis.In Chapter 5, we developed two new sets of microsatellite primers (SSRs); 16 primer pairs for Prioria balsamifera and 15 primer pairs for Prioria oxyphylla. Validation of the primers in two populations of each species, as well as the cross-amplification tests, demonstrated the usefulness of the SSRs to study gene flow and spatial genetic structure in African Prioria species, which is needed to prevent genetic erosion and to set up proper conservation guidelines.In Chapter 6, the 16 newly developed microsatellite loci were amplified in individuals of P. balsamifera from Gabon and the Democratic Republic of the Congo, to assess the levels of genetic diversity and intraspecific differentiation. Our analyses show that the genetic diversity in P. balsamifera populations is relatively low, so efforts should be made to prevent further depletion of the gene pool. Bayesian clustering analyses revealed multiple genetic discontinuities throughout the Congo Basin, probably caused by ancient forest fragmentation. The inferred intraspecific clusters show a parapatric distribution, so they can potentially be used to determine the origin of individuals at a regional scale. Additionally, various genetic assignment methods show that the SSR dataset generated in this study can be used as a reference database for Gabon and DR Congo. The general discussion allows us to show similarities in the genetic structures of species that can be interpreted in terms of forest cover history in Central Africa.Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe
Evidence of past forest fragmentation in the Congo Basin from the phylogeography of a shade-tolerant tree with limited seed dispersal: Scorodophloeus zenkeri (Fabaceae, Detarioideae)
No full textBackground: Comparative phylogeographic studies on rainforest species that are widespread in Central Africa often reveal genetic discontinuities within and between biogeographic regions, indicating (historical) barriers to gene flow, possibly due to repeated and/or long-lasting population fragmentation during glacial periods according to the forest refuge hypothesis. The impact of forest fragmentation seems to be modulated by the ecological amplitude and dispersal capacities of each species, resulting in different demographic histories. Moreover, while multiple studies investigated the western part of Central Africa (Lower Guinea), few have sufficiently sampled the heart of the Congo Basin (Congolia). In this study, we look for genetic discontinuities between populations of the widespread tropical tree Scorodophloeus zenkeri Harms (Fabaceae, Detarioideae) in Central Africa. Additionally, we characterize genetic diversity, selfing rate and fine-scale spatial genetic structure within populations to estimate the gene dispersal capacity of the species. Results: Clear intraspecific genetic discontinuities occur throughout the species’ distribution range, with two genetic clusters in Congolia and four in Lower Guinea, and highest differentiation occurring between these bioregions. Genetic diversity is higher in Lower Guinea than Congolia. A spatial genetic structure characteristic of isolation by distance occurs within the genetic clusters. This allowed us to estimate gene dispersal distances (σg) for this outcrossing species with ballistic seed dispersal, which range between 100 and 250 m in areas where S. zenkeri occurs in high densities, and are in the low range of σg values compared to other tropical trees. Gene dispersal distances are larger in low density populations, probably due to extensive pollen dispersal capacity. Conclusions: Fragmentation of S. zenkeri populations seems to have occurred not only in Lower Guinea but also in the Congo Basin, though not necessarily according to previously postulated forest refuge areas. The lower genetic diversity in Congolia compared to Lower Guinea parallels the known gradient of species diversity, possibly reflecting a stronger impact of past climate changes on the forest cover in Congolia. Despite its bisexual flowers, S. zenkeri appears to be mostly outcrossing. The limited dispersal observed in this species implies that genetic discontinuities resulting from past forest fragmentation can persist for a long time before being erased by gene flow.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Phylogenomic analysis clarifies the evolutionary origin of Coffea arabica L
No full textSummary Interspecific hybridization events have played a major role in plant speciation, yet, the evolutionary origin of hybrid species often remains enigmatic. Here, we inferred the evolutionary origin of the allotetraploid species Coffea arabica , which is widely cultivated for Arabica coffee production. We estimated genetic distances between C. arabica and all species that are known to be closely related to C. arabica using genotyping-by-sequencing (GBS) data. In addition, we reconstructed a time-calibrated multilabeled phylogenetic tree of 24 species to infer the age of the C. arabica hybridization event. Ancestral states of self-compatibility were also reconstructed to infer the evolution of self-compatibility in Coffea . C. canephora and C. eugenioides were confirmed as the putative progenitor species of C. arabica. These species most likely hybridized between 1.08 million and 543 thousand years ago. We inferred the phylogenetic relationships between C. arabica and its closest relatives and shed new light on the evolution of self-compatibility in Coffea . Furthermore, the age of the hybridization event coincides with periods of environmental upheaval, which may have induced range shifts of the progenitor species that facilitated the emergence of C. arabica .sponsorship: We thank Cephas Masumbuko Ndabaga, Eberhard Fischer, Samuel Vanden Abeele, and Filip Vandelook for collecting plant material, and Sabine Van Glabeke, Guy Baele, and Zyon Vansteelandt for their technical support. We are also grateful to the anonymous reviewers for their valuable comments that improved the manuscript. This research was funded by Research Foundation-Flanders (FWO) (Project No. G056517N). (Research Foundation-Flanders (FWO)|G056517N)status: Published onlin
Aligning EU policies to address biological invasions: assessing invasion impacts across sectors
No full textInvasive alien species (IAS) affect various policy sectors, including environment, trade, and agriculture. In Europe, each of these sectors is usually regulated under different European Union legislation, but IAS is not prioritised in most sectors, and this may hinder effective tackling of biological invasions. Greater policy coherence is needed to align relevant sectors for better management of biological invasions. Engaging policymakers by sharing information on IAS impacts can help them understand the multisectoral nature of the problem and develop effective strategies.
We reviewed 602 IAS in Europe, impacting nine policy sectors and 25 domains (i.e. specific policies within a broader policy sector, each addressing particular issues and activities related to that sector portfolio). Findings were presented at the NeoBiota workshop in Lisbon on the 3rd of September 2024, attended by 54 participants, including policymakers and researchers. The workshop featured presentations and interactive sessions where participants tested the review methodology on 49 species, identifying areas for improvement, such as assessing impact scale and refining sector domains. Confusion matrices showed moderate to substantial agreement between organisers and participants in evaluating affected domains, types of impact, and confidence levels.
This study shows the crucial need for interaction and synergy between research and policy, which are essential for tackling effectively IAS in Europe
Report.“Exploration of wild banana populations in Papua New Guinea”, 7-17 June 2017
No full textThis report documents the exploration of wild banana populations on the East coast of Papua New Guinea in June, 2017, with the aim of collecting wild specimens for population genetics studies. The collecting team visited two provinces on the East coast: in Madang province, they collected samples of M. acuminata banksii M. schizocarpa and M. peekelii ssp. angustigemmawhile M. acuminata ssp. banksii, M. schizocarpa, M. maclayi spp. maclayi var maclayi and M. balbisiana were collected in Morobe Province. In addition to leaf samples, seeds were also collected that will be studied and conserved as part of the ITC Musa seedbank being established by Bioversity International and the Botanical Garden of Meis
Genetic Markers for Species Conservation and Timber Tracking: Development of Microsatellite Primers for the Tropical African Tree Species Prioria balsamifera and Prioria oxyphylla
No full textResearch Highlights: Two novel sets of polymorphic microsatellite markers were developed for Prioria balsamifera and Prioria oxyphylla through high-throughput sequencing. Validation in two populations of each species proved the utility of the developed primers to estimate genetic diversity at population level. Background and Objectives: Prioria balsamifera and Prioria oxyphylla are tropical tree species from Central Africa. They produce a high-quality, multi-purpose timber that is of great interest to the international market. Prioria balsamifera has been included as ‘endangered’ on the IUCN Red List of Threatened Species. In order to set up adequate management plans and facilitate timber tracking, knowledge on the genetic diversity at population level is needed. Therefore, we aim to develop microsatellite markers that can be used for species conservation, forensics, plant breeding and population genetics studies. Materials and Methods: Genomic DNA of P. balsamifera and P. oxyphylla was sequenced on an Illumina NextSeq platform (Illumina Inc. San Diego, CA, USA), generating 829,421 and 772,018 paired-end reads that contained 7148 and 7004 microsatellite sequences, respectively. The QDD-pipeline was used to design primers, which were tested for amplification in two populations of each species. Cross-species amplification was tested in all seven African Prioria species. Results: For P. balsamifera, 16 polymorphic microsatellite markers were developed and combined in three multiplexes. Inbreeding appeared to be absent but genetic diversity was low in both populations. For P. oxyphylla, 15 polymorphic microsatellite markers were developed and combined in three multiplexes. Genetic diversity was low in both populations and estimated null allele frequencies were high for multiple loci. Cross-species amplification tests demonstrated the occurrence of conserved loci that amplified for most of the African Prioria species. Conclusions: The microsatellite markers prove to be useful for estimating genetic diversity at population level. These novel markers can be used to study gene flow and spatial genetic structure in Prioria species, which is needed to set up proper conservation guidelines and to prevent genetic erosion.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Isolation of microsatellite loci in the African tree species Staudtia kamerunensis (Myristicaceae) using high-throughput sequencing
No full textStaudtia kamerunensis (Myristicaceae) or ‘Niové’ is an evergreen tree widespread in Central African moist forests. The bark and seeds are used in traditional medicine, yet the tree is mainly harvested for its high quality, multi-purpose timber. To facilitate sustainable harvesting and conservation of the species, we aim to develop microsatellite markers that can be used to study the mating system, gene flow, genetic diversity and population structure. Genomic DNA of S. kamerunensis was sequenced on an Illumina MiSeq platform, generating 195,720 paired-end reads with 3671 sequences containing microsatellites. Amplification tests resulted in the development of 16 highly polymorphic microsatellite loci of which 14 were tested in 183 individuals of S. kamerunensis from three populations. The number of detected alleles per locus ranged from 15 to 39 and the average observed and expected heterozygosity across loci and populations were Ho = 0.713 (0.14–0.97) and He = 0.879 (0.19–0.95) respectively. The high levels of polymorphism observed in the newly developed microsatellite markers demonstrate their usefulness to study gene flow, population structure and spatial distribution of genetic diversity in S. kamerunensis.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Spatial variability of iron, zinc and selenium content in faba bean (Vicia faba L.) seeds from central and southwestern highlands of Ethiopia
No full textAims This study has been carried out to determine the spatial variability of faba bean seed Fe, Zn and Se content across agro-ecological zones in central and southwestern Ethiopia, where it is an important source of protein in the diet. The study assessed whether soil properties, arbuscular mycorrhizal fungi (AMF), faba bean characteristics and genetic diversity and agro-ecological zone as random factor affect seed Fe, Zn and Se content. Methodology Multi-location fields were sampled in three important faba bean growing agro-ecologies during the 2018-2019 cropping season. Results Seed Fe content varied from 45.7-61.9, 41.6-102 and 31.1-77.0 mg kg(-1) in Cheliya, Dedo and Dendi, respectively. Likewise, Zn content ranged from 38.3-56.3, 44.6-73.6 and 21.6-49.9 mg kg(-1). Selenium content varied from 10.1-45.1, 12.1-160 and 16.2-167 mu g kg(-1). Significant differences were observed for Zn and Se content across agro-ecologies. Consumption of 100 g faba beans per day can provide an overall average of 64 and 28% of the recommended daily allowance (RDA) for Fe, 45 and 62% for Zn and only 8% for Se for male and female adults, respectively. Soil properties explained seed Fe, Zn and Se content variation. However, for Zn and Se content the largest share of the difference was explained by agro-ecological mediated environmental variations. As a consequence, differences in dietary intake of micro-nutrients via faba beans are determined by living area. Conclusion Soil properties and especially agro-ecological mediated environmental conditions explained seed Zn and Se content of faba bean and hence potential dietary intake
