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| 2. |
- Romagnoni, A, et al.
(author)
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Comparative performances of machine learning methods for classifying Crohn Disease patients using genome-wide genotyping data
- 2019
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In: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1, s. 10351-
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Journal article (peer-reviewed)abstract
- Crohn Disease (CD) is a complex genetic disorder for which more than 140 genes have been identified using genome wide association studies (GWAS). However, the genetic architecture of the trait remains largely unknown. The recent development of machine learning (ML) approaches incited us to apply them to classify healthy and diseased people according to their genomic information. The Immunochip dataset containing 18,227 CD patients and 34,050 healthy controls enrolled and genotyped by the international Inflammatory Bowel Disease genetic consortium (IIBDGC) has been re-analyzed using a set of ML methods: penalized logistic regression (LR), gradient boosted trees (GBT) and artificial neural networks (NN). The main score used to compare the methods was the Area Under the ROC Curve (AUC) statistics. The impact of quality control (QC), imputing and coding methods on LR results showed that QC methods and imputation of missing genotypes may artificially increase the scores. At the opposite, neither the patient/control ratio nor marker preselection or coding strategies significantly affected the results. LR methods, including Lasso, Ridge and ElasticNet provided similar results with a maximum AUC of 0.80. GBT methods like XGBoost, LightGBM and CatBoost, together with dense NN with one or more hidden layers, provided similar AUC values, suggesting limited epistatic effects in the genetic architecture of the trait. ML methods detected near all the genetic variants previously identified by GWAS among the best predictors plus additional predictors with lower effects. The robustness and complementarity of the different methods are also studied. Compared to LR, non-linear models such as GBT or NN may provide robust complementary approaches to identify and classify genetic markers.
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| 3. |
- Garibaldi, Lucas A., et al.
(author)
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Wild Pollinators Enhance Fruit Set of Crops Regardless of Honey Bee Abundance
- 2013
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 339:6127, s. 1608-1611
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Journal article (peer-reviewed)abstract
- The diversity and abundance of wild insect pollinators have declined in many agricultural landscapes. Whether such declines reduce crop yields, or are mitigated by managed pollinators such as honey bees, is unclear. We found universally positive associations of fruit set with flower visitation by wild insects in 41 crop systems worldwide. In contrast, fruit set increased significantly with flower visitation by honey bees in only 14% of the systems surveyed. Overall, wild insects pollinated crops more effectively; an increase in wild insect visitation enhanced fruit set by twice as much as an equivalent increase in honey bee visitation. Visitation by wild insects and honey bees promoted fruit set independently, so pollination by managed honey bees supplemented, rather than substituted for, pollination by wild insects. Our results suggest that new practices for integrated management of both honey bees and diverse wild insect assemblages will enhance global crop yields.
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| 4. |
- Teslovich, Tanya M., et al.
(author)
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Biological, clinical and population relevance of 95 loci for blood lipids
- 2010
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 466:7307, s. 707-713
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Journal article (peer-reviewed)abstract
- Plasma concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides are among the most important risk factors for coronary artery disease (CAD) and are targets for therapeutic intervention. We screened the genome for common variants associated with plasma lipids in >100,000 individuals of European ancestry. Here we report 95 significantly associated loci (P<5 x 10(-8)), with 59 showing genome-wide significant association with lipid traits for the first time. The newly reported associations include single nucleotide polymorphisms (SNPs) near known lipid regulators (for example, CYP7A1, NPC1L1 and SCARB1) as well as in scores of loci not previously implicated in lipoprotein metabolism. The 95 loci contribute not only to normal variation in lipid traits but also to extreme lipid phenotypes and have an impact on lipid traits in three non-European populations (East Asians, South Asians and African Americans). Our results identify several novel loci associated with plasma lipids that are also associated with CAD. Finally, we validated three of the novel genes-GALNT2, PPP1R3B and TTC39B-with experiments in mouse models. Taken together, our findings provide the foundation to develop a broader biological understanding of lipoprotein metabolism and to identify new therapeutic opportunities for the prevention of CAD.
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| 5. |
- Droste, Nils, et al.
(author)
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Designing a global mechanism for intergovernmental biodiversity financing
- 2019
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In: Conservation Letters. - : Wiley. - 1755-263X. ; 12:6
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Journal article (peer-reviewed)abstract
- The Convention on Biological Diversity and the Nagoya Protocol display a broad international consensus for biodiversity conservation and equitable benefit sharing. Yet, the Aichi biodiversity targets show a lack of progress and thus indicate a need for additional action such as enhanced and better targeted financial resource mobilization. To date, no global financial burden-sharing instrument has been proposed. Developing a global-scale financial mechanism to support biodiversity conservation through intergovernmental transfers, we simulate three allocation designs: ecocentric, socioecological, and anthropocentric. We analyze the corresponding incentives needed to reach the Aichi target of terrestrial protected area coverage by 2020. Here we show that the socioecological design would provide the strongest median incentive for states which are farthest from achieving the target. Our proposal provides a novel concept for global biodiversity financing, which can serve as a starting point for more specific policy dialogues on intergovernmental burden and benefit-sharing mechanisms to halt biodiversity loss.
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| 6. |
- Garibaldi, Lucas A., et al.
(author)
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Trait matching of flower visitors and crops predicts fruit set better than trait diversity
- 2015
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In: Journal of Applied Ecology. - : Wiley. - 1365-2664 .- 0021-8901. ; 52:6, s. 1436-1444
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Research review (peer-reviewed)abstract
- Understanding the relationships between trait diversity, species diversity and ecosystem functioning is essential for sustainable management. For functions comprising two trophic levels, trait matching between interacting partners should also drive functioning. However, the predictive ability of trait diversity and matching is unclear for most functions, particularly for crop pollination, where interacting partners did not necessarily co-evolve. World-wide, we collected data on traits of flower visitors and crops, visitation rates to crop flowers per insect species and fruit set in 469 fields of 33 crop systems. Through hierarchical mixed-effects models, we tested whether flower visitor trait diversity and/or trait matching between flower visitors and crops improve the prediction of crop fruit set (functioning) beyond flower visitor species diversity and abundance. Flower visitor trait diversity was positively related to fruit set, but surprisingly did not explain more variation than flower visitor species diversity. The best prediction of fruit set was obtained by matching traits of flower visitors (body size and mouthpart length) and crops (nectar accessibility of flowers) in addition to flower visitor abundance, species richness and species evenness. Fruit set increased with species richness, and more so in assemblages with high evenness, indicating that additional species of flower visitors contribute more to crop pollination when species abundances are similar.Synthesis and applications. Despite contrasting floral traits for crops world-wide, only the abundance of a few pollinator species is commonly managed for greater yield. Our results suggest that the identification and enhancement of pollinator species with traits matching those of the focal crop, as well as the enhancement of pollinator richness and evenness, will increase crop yield beyond current practices. Furthermore, we show that field practitioners can predict and manage agroecosystems for pollination services based on knowledge of just a few traits that are known for a wide range of flower visitor species. Despite contrasting floral traits for crops world-wide, only the abundance of a few pollinator species is commonly managed for greater yield. Our results suggest that the identification and enhancement of pollinator species with traits matching those of the focal crop, as well as the enhancement of pollinator richness and evenness, will increase crop yield beyond current practices. Furthermore, we show that field practitioners can predict and manage agroecosystems for pollination services based on knowledge of just a few traits that are known for a wide range of flower visitor species. Editor's Choice
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| 7. |
- Sawcer, Stephen, et al.
(author)
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Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis
- 2011
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 476:7359, s. 214-219
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Journal article (peer-reviewed)abstract
- Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis.
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| 8. |
- Eeraerts, Maxime, et al.
(author)
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Pollination deficits and their relation with insect pollinator visitation are cultivar-dependent in an entomophilous crop
- 2024
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In: Agriculture, Ecosystems and Environment. - 0167-8809. ; 369
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Journal article (peer-reviewed)abstract
- Insects contribute considerably to global crop pollination, with pollination deficits being documented for multiple entomophilous or pollinator-dependent crops. Different cultivars of crops are being cultivated within and across production regions, so it is essential to understand the cultivar variability of pollination deficits. Here, we used a dataset from 286 sites from multiple production regions to develop a synthesis on pollination deficits in two widely cultivated highbush blueberry cultivars, ‘Bluecrop’ and ‘Duke’. Additionally, we determined if bee visitation or bee richness reduces pollination deficits in these cultivars. On average, neither cultivar showed pollination deficits regarding fruit set. However, for ‘Bluecrop’ we found pollination deficits for berry weight and seed set, which was not the case for ‘Duke’. Increasing total bee visitation reduced pollination deficits of both berry weight and seed set for ‘Bluecrop’. More specifically, a non-linear, negative exponential model best predicted this relation between bee visitation and pollination deficits. Our results highlight that pollination deficits and responses to pollinator visitation are variable between different cultivars of a single crop, which suggests opportunities to use certain cultivars that are less dependent on insect-mediated pollination in landscapes and regions where pollination services have been compromised. In addition, the non-linear response between bee visitation and pollination deficits suggests that optimal bee visitation rates need to be determined to improve pollination management and crop yield and to support accurate economic valuations of pollination services.
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| 9. |
- Eeraerts, Maxime, et al.
(author)
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Synthesis of highbush blueberry pollination research reveals region-specific differences in the contributions of honeybees and wild bees
- 2023
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In: Journal of Applied Ecology. - 0021-8901. ; 60:12, s. 2528-2539
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Research review (peer-reviewed)abstract
- Highbush blueberry production has expanded worldwide in recent decades. To safeguard future yields, it is essential to understand if insect pollination is limiting current blueberry production and which insects contribute to pollination in different production regions. We present a systematic review including a set of meta-analyses on insect-mediated pollination in highbush blueberry. We summarize the geographic distribution of research, the abundance of different pollinator taxa and their relative pollination contributions. Using raw data from 21 studies, totalling 496 site replicates, we determine the degree of pollination service and pollen limitation (i.e. combining open pollination levels with experimental bagged and/or hand pollination treatments), as well as the contribution of honeybees and wild bees to pollination (i.e. observational, open pollination). Most studies originate from North America, focusing on only a few cultivars. Honeybees are the dominant pollinator, and wild bees are occasionally abundant. Wild bees are more efficient pollinators on a single-visit basis compared to honeybees, which increases their relative pollination contribution compared to their relative abundance. Insect-mediated pollination services increased blueberry fruit set, berry weight and seed set (R2 values: 64.8%, 75.9% and 75.2% respectively). We often detected pollen limitation, indicated by an increase in fruit set, berry weight and seed set (R2: 10.1%, 18.2% and 21.5%, respectively), with additional hand pollination. Increasing visitation of honeybees and wild bees contributed to blueberry pollination by increasing fruit set (R2: 5.4% and 3.5%), berry weight (R2: 6.5% and 2.8%) and seed set (R2: 6.4% and 3.8%) respectively. Bee contributions to fruit set and berry weight were variable across regions. Synthesis and application: A diverse community of insects, primarily bees, contributes to highbush blueberry pollination and yield. However, pollination deficits are common. The finding that both honeybees and wild bees enhance pollination highlights the possibility of adopting different management strategies that utilize honeybees, wild bees or both depending on the specific context and region. This further emphasizes the general importance of conserving pollinator health and diversity. Our synthesis highlights data gaps and areas for future research to better understand the pollination contribution of different pollinators to crops that are expanding globally.
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| 10. |
- Gourevitch, Jesse D., et al.
(author)
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Projected losses of ecosystem services in the US disproportionately affect non-white and lower-income populations
- 2021
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12
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Journal article (peer-reviewed)abstract
- Addressing how ecosystem services (ES) are distributed among groups of people is critical for making conservation and environmental policy-making more equitable. Here, we evaluate the distribution and equity of changes in ES benefits across demographic and socioeconomic groups in the United States (US) between 2020 and 2100. Specifically, we use land cover and population projections to model potential shifts in the supply, demand, and benefits of the following ES: provision of clean air, protection against a vector-borne disease (West Nile virus), and crop pollination. Across the US, changes in ES benefits are unevenly distributed among socioeconomic and demographic groups and among rural and urban communities, but are relatively uniform across geographic regions. In general, non-white, lower-income, and urban populations disproportionately bear the burden of declines in ES benefits. This is largely driven by the conversion of forests and wetlands to cropland and urban land cover in counties where these populations are expected to grow. In these locations, targeted land use policy interventions are required to avoid exacerbating inequalities already present in the US.
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