scholarly journals Monitoring Needs for Gene Drive Mosquito Projects: Lessons From Vector Control Field Trials and Invasive Species

2022 ◽  
Vol 12 ◽  
Author(s):  
Gordana Rašić ◽  
Neil F. Lobo ◽  
Eileen H. Jeffrey Gutiérrez ◽  
Héctor M. Sánchez C. ◽  
John M. Marshall
Keyword(s):  
Invasive Species ◽  
Field Testing ◽  
Field Trials ◽  
Resistance Mechanisms ◽  
Small Scale ◽  
Gene Drive ◽  
Population Replacement ◽  
Effector Genes ◽  
Population Suppression ◽  
Suppression Systems

As gene drive mosquito projects advance from contained laboratory testing to semi-field testing and small-scale field trials, there is a need to assess monitoring requirements to: i) assist with the effective introduction of the gene drive system at field sites, and ii) detect unintended spread of gene drive mosquitoes beyond trial sites, or resistance mechanisms and non-functional effector genes that spread within trial and intervention sites. This is of particular importance for non-localized gene drive projects, as the potential scale of intervention means that monitoring is expected to be more costly than research, development and deployment. Regarding monitoring needs for population replacement systems, lessons may be learned from experiences with Wolbachia-infected mosquitoes, and for population suppression systems, from experiences with releases of genetically sterile male mosquitoes. For population suppression systems, assessing monitoring requirements for tracking population size and detecting rare resistant alleles are priorities, while for population replacement systems, allele frequencies must be tracked, and pressing concerns include detection of gene drive alleles with non-functional effector genes, and resistance of pathogens to functional effector genes. For spread to unintended areas, open questions relate to the optimal density and placement of traps and frequency of sampling in order to detect gene drive alleles, drive-resistant alleles or non-functional effector genes while they can still be effectively managed. Invasive species management programs face similar questions, and lessons may be learned from these experiences. We explore these monitoring needs for gene drive mosquito projects progressing through the phases of pre-release, release and post-release.

scholarly journals Antiviral Effectors and Gene Drive Strategies for Mosquito Population Suppression or Replacement to Mitigate Arbovirus Transmission by Aedes aegypti

Insects ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 52 ◽  
Author(s):  
Adeline Williams ◽  
Alexander Franz ◽  
William Reid ◽  
Ken Olson
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Mosquito Control ◽  
Control Strategies ◽  
Mosquito Vector ◽  
Close Monitoring ◽  
Gene Drive ◽  
Population Replacement ◽  
Effector Genes ◽  
Population Suppression

The mosquito vector Aedes aegypti transmits arthropod-borne viruses (arboviruses) of medical importance, including Zika, dengue, and yellow fever viruses. Controlling mosquito populations remains the method of choice to prevent disease transmission. Novel mosquito control strategies based on genetically manipulating mosquitoes are being developed as additional tools to combat arbovirus transmission. Genetic control of mosquitoes includes two basic strategies: population suppression and population replacement. The former aims to eliminate mosquito populations while the latter aims to replace wild populations with engineered, pathogen-resistant mosquitoes. In this review, we outline suppression strategies being applied in the field, as well as current antiviral effector genes that have been characterized and expressed in transgenic Ae. aegypti for population replacement. We discuss cutting-edge gene drive technologies that can be used to enhance the inheritance of effector genes, while highlighting the challenges and opportunities associated with gene drives. Finally, we present currently available models that can estimate mosquito release numbers and time to transgene fixation for several gene drive systems. Based on the recent advances in genetic engineering, we anticipate that antiviral transgenic Ae. aegypti exhibiting gene drive will soon emerge; however, close monitoring in simulated field conditions will be required to demonstrate the efficacy and utility of such transgenic mosquitoes.

scholarly journals Experts’ moral views on gene drive technologies: a qualitative interview study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
N. de Graeff ◽  
Karin R. Jongsma ◽  
Annelien L. Bredenoord
Keyword(s):  
Invasive Species ◽  
Epistemic Uncertainty ◽  
Field Trials ◽  
Interview Study ◽  
Gene Drive ◽  
Agricultural Pests ◽  
Stepping Stones ◽  
Vector Borne Diseases ◽  
Qualitative Interview Study ◽  
The Status

Abstract Background Gene drive technologies (GDTs) promote the rapid spread of a particular genetic element within a population of non-human organisms. Potential applications of GDTs include the control of insect vectors, invasive species and agricultural pests. Whether, and if so, under what conditions, GDTs should be deployed is hotly debated. Although broad stances in this debate have been described, the convictions that inform the moral views of the experts shaping these technologies and related policies have not been examined in depth in the academic literature. Methods In this qualitative study, we interviewed GDT experts (n = 33) from different disciplines to identify and better understand their moral views regarding these technologies. The pseudonymized transcripts were analyzed thematically. Results The respondents’ moral views were principally influenced by their attitudes towards (1) the uncertainty related to GDTs; (2) the alternatives to which they should be compared; and (3) the role humans should have in nature. Respondents agreed there is epistemic uncertainty related to GDTs, identified similar knowledge gaps, and stressed the importance of realistic expectations in discussions on GDTs. They disagreed about whether uncertainty provides a rationale to refrain from field trials (‘risks of intervention’ stance) or to proceed with phased testing to obtain more knowledge given the harms of the status quo (‘risks of non-intervention’ stance). With regards to alternatives to tackle vector-borne diseases, invasive species and agricultural pests, respondents disagreed about which alternatives should be considered (un)feasible and (in)sufficiently explored: conventional strategies (‘downstream solutions’ stance) or systematic changes to health care, political and agricultural systems (‘upstream solutions’ stance). Finally, respondents held different views on nature and whether the use of GDTs is compatible with humans’ role in nature (‘interference’ stance) or not (‘non-interference stance’). Conclusions This interview study helps to disentangle the debate on GDTs by providing a better understanding of the moral views of GDT experts. The obtained insights provide valuable stepping-stones for a constructive debate about underlying value conflicts and call attention to topics that deserve further (normative) reflection. Further evaluation of these issues can facilitate the debate on and responsible development of GDTs.

scholarly journals Integral Gene Drives: an “operating system” for population replacement

2018 ◽  
Author(s):  
Alexander Nash ◽  
Giulia Mignini Urdaneta ◽  
Andrea K. Beaghton ◽  
Astrid Hoermann ◽  
Philippos Aris Papathanos ◽  
...  
Keyword(s):  
Field Testing ◽  
Target Site ◽  
Gene Drive ◽  
Population Replacement ◽  
Pathogen Effector ◽  
Site Variation ◽  
The Face ◽  
Endogenous Genes ◽  
Target Site Resistance ◽  
Gene Drives

AbstractFirst generation CRISPR-based gene drives have now been tested in the laboratory in a number of organisms including malaria vector mosquitoes. A number of challenges for their use in the area-wide genetic control of vector-borne disease have been identified. These include the development of target site resistance, their long-term efficacy in the field, their molecular complexity, and the practical and legal limitations for field testing of both gene drive and coupled anti-pathogen traits. To address these challenges, we have evaluated the concept of Integral Gene Drive (IGD) as an alternative paradigm for population replacement. IGDs incorporate a minimal set of molecular components, including both the drive and the anti-pathogen effector elements directly embedded within endogenous genes – an arrangement which we refer to as gene “hijacking”. This design would allow autonomous and non-autonomous IGD traits and strains to be generated, tested, optimized, regulated and imported independently. We performed quantitative modelling comparing IGDs with classical replacement drives and show that selection for the function of the hijacked host gene can significantly reduce the establishment of resistant alleles in the population while hedging drive over multiple genomic loci prolongs the duration of transmission blockage in the face of pre-existing target-site variation. IGD thus has the potential to yield more durable and flexible population replacement traits.

scholarly journals Tethered homing gene drives: a new design for spatially restricted population replacement and suppression

2018 ◽  
Author(s):  
Sumit Dhole ◽  
Alun L. Lloyd ◽  
Fred Gould
Keyword(s):  
Mathematical Model ◽  
Genetic Load ◽  
Target Population ◽  
Gene Drive ◽  
Population Replacement ◽  
Additional Release ◽  
New Gene ◽  
Gene Drives ◽  
Population Suppression ◽  
Proof Of Principle

ABSTRACTOptimism regarding potential epidemiological and conservation applications of modern gene drives is tempered by concern about the potential unintended spread of engineered organisms beyond the target population. In response, several novel gene drive approaches have been proposed that can, under certain conditions, locally alter characteristics of a population. One challenge for these gene drives is the difficulty of achieving high levels of localized population suppression without very large releases in face of gene flow. We present a new gene drive system, Tethered Homing (TH), with improved capacity for localized population alteration, especially for population suppression. The TH drive is based on driving a payload gene using a homing construct that is anchored to a spatially restricted gene drive. We use a proof of principle mathematical model to show the dynamics of a TH drive that uses engineered underdominance as an anchor. This system is composed of a split homing drive and a two-locus engineered underdominance drive linked to one part of the split drive (the Cas endonuclease). In addition to improved localization, the TH system offers the ability to gradually adjust the genetic load in a population after the initial alteration, with minimal additional release effort.

scholarly journals Small-scale release of non-gene drive mosquitoes in Burkina Faso: from engagement implementation to assessment, a learning journey

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Lea Pare Toe ◽  
Nourou Barry ◽  
Anselme D. Ky ◽  
Souleymane Kekele ◽  
Wilfrid Meda ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Stakeholder Engagement ◽  
Research Process ◽  
Field Trials ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Small Scale ◽  
Gene Drive ◽  
Assessment Framework ◽  
Responsible Research

Abstract Background Innovative tools are needed to complement the existing approach for malaria elimination. Gene drive mosquitoes are one potential new technology in the control of malaria vectors. Target Malaria is one of the research projects developing this technology, and in July 2019, the project proceeded to an important step for this evaluation pathway: the small-scale release of non-gene drive sterile male mosquitoes in a village in Burkina Faso. In addition to the entomological and laboratory work to prepare for this important milestone, significant community and stakeholder engagement work was done. The existing guidelines on gene drive mosquito provide an overall framework for such engagement work. However, they do not provide a road map on how to proceed or what benchmarks should be used to assess this work. Methods This study provides a review of engagement activities relevant to field trials on non-gene drive genetically-modified mosquitoes as well as an assessment framework—using both qualitative and quantitative studies as well as an audit procedure. The latter was implemented to evaluate whether the release activities could proceed with the appropriate level of agreement from the community. Results This paper shows the importance of this first phase of work to innovate and learn about engagement processes for responsible research in the field of genetic approaches for malaria vector control. The function of these assessments is crucial for the learning agenda. The assessments demonstrated ways to increase understanding and ensure effective progress with field studies and, therefore, the pathway for responsible research. Conclusion Gene drive technology is increasingly considered as a promising approach to control vector borne diseases, in particular malaria. Stakeholders’ involvement in this research process is one of the recurring requirements in international guidance documents. With this paper Target Malaria offers an opportunity to explore the practical achievements and challenges of stakeholder engagement during early phases of a technology evaluation, and in particular how it implemented an assessment framework to learn from its experience.

scholarly journals Development and testing of a novel killer–rescue self-limiting gene drive system in Drosophila melanogaster

2020 ◽  
Vol 287 (1925) ◽  
pp. 20192994 ◽  
Author(s):  
Sophia H. Webster ◽  
Michael R. Vella ◽  
Maxwell J. Scott
Keyword(s):  
Drosophila Melanogaster ◽  
Aedes Aegypti ◽  
Drive System ◽  
R Gene ◽  
Agricultural Pest ◽  
Gene Drive ◽  
Wild Type ◽  
Drosophila Suzukii ◽  
Population Replacement ◽  
Population Suppression

Here we report the development and testing of a novel self-limiting gene drive system, Killer–Rescue (K–R), in Drosophila melanogaster . This system is composed of an autoregulated Gal4 Killer (K) and a Gal4-activated Gal80 Rescue (R). Overexpression of Gal4 is lethal, but in the presence of R activation of Gal80 leads to much lower levels of Gal4 and rescue of lethality. We demonstrate that with a single 2 : 1 engineered to wild-type release, K drives R through the population and after nine generations, more than 98% of the population carry R and less than 2% of the population are wild-type flies. We discuss how this simple K–R gene drive system may be readily adapted for population replacement in a human health pest, Aedes aegypti , or for population suppression in an agricultural pest, Drosophila suzukii .

Grain mineral density of bread and durum wheat landraces from geochemically diverse native soils

2018 ◽  
Vol 69 (4) ◽  
pp. 335 ◽  
Author(s):  
José Francisco Vázquez ◽  
Efraín Antonio Chacón ◽  
José María Carrillo ◽  
Elena Benavente
Keyword(s):  
Durum Wheat ◽  
Triticum Aestivum L ◽  
Field Trials ◽  
Mineral Elements ◽  
Small Scale ◽  
Mineral Density ◽  
Native Soil ◽  
Wide Range ◽  
Grain Zinc ◽  
Wheat Landraces

Future progress on the creation of wheat cultivars with high grain zinc (Zn) and iron (Fe) mineral density will depend on both the availability of suitable donor germplasm and the identification of genes or quantitative trait loci contributing to increase the accumulation of mineral elements in the wheat kernels. Multi-environment field trials were conducted to evaluate the grain Zn, Fe and protein concentration of 32 bread wheat (Triticum aestivum L.) and 20 durum wheat (T. turgidum L. var. durum) landraces locally adapted to soils covering a wide range of pH values and mineral composition. These landraces were selected after a preliminary, small-scale field trial that had analysed 425 Spanish local varieties. Analyses of variance demonstrated a significant effect of genotype on grain composition, and 16 wheat landraces with elevated grain Zn and/or Fe density across the environments were identified. These landraces rich in grain minerals represent valuable primary gene-pool parents for wheat biofortification. No pattern of native soil geochemical characteristics that could help to predict the success in collecting mineral-dense genotypes in a given area was found. Mapping populations derived from some pairs of grain-mineral-rich and -poor genotypes characterised in the study may facilitate the development of molecular markers to assist the selection of superior wheat genotypes.

scholarly journals DUNE STABILIZATION WITH A SAND/GEL COMPOSITE SYSTEM

1988 ◽  
Vol 1 (21) ◽  
pp. 118
Author(s):  
M.H. Auerbach ◽  
G.W. Borden ◽  
B.L. Edge
Keyword(s):  
Composite System ◽  
Coastal Dunes ◽  
Field Testing ◽  
Field Trials ◽  
Beach Sand ◽  
Front Face ◽  
Initial Development ◽  
Wave Research ◽  
And Performance ◽  
Temporary Stabilization

The effectiveness of a novel sand/gel composite system for the temporary stabilization of coastal dunes was demonstrated in wavetank and field testing. The composite consists of 97% beach sand and water, with a few percent of a biodegradable aqueous polymeric gel made from nontoxic ingredients. The gel binds the sand into a firm but resilient composite that is natural in appearance and resists erosion from waves and tides. The composite is applied by pneumatic gun to the front face of a dune to a few feet below the berm level for toe protection. This paper describes the initial development and performance of the composite system in wavetank tests at the Oregon State University Wave Research Facility and field trials at Anastasia State Park, St. Augustine, Florida; Chuck's Steak House, Melbourne Beach, Florida; and Ocean Dunes Condominiums, Fort Fisher, North Carolina.

scholarly journals Modifikasi alat cakram untuk proses pembelajaran

2021 ◽  
Vol 2 (2) ◽  
pp. 180-188
Author(s):  
Laras Gita Kinanti ◽  
Utvi Hinda Zhannisa ◽  
Tubagus Herlambang
Keyword(s):  
Physical Education ◽  
Large Scale ◽  
Field Trials ◽  
Small Scale ◽  
Plate Waste ◽  
Education Material ◽  
Teachers And Students ◽  
Student Questionnaire ◽  
Scale Test ◽  
Expert Validation

The purpose of this research is to modify a simple disc device for learning physical education. The research method used was the development of Borg & Gall, namely (1) collecting information, (2) developing the initial form (in the form of a disc tool model), (3) expert validation testing, namely using 1 validation of athletic experts and one physical education learning expert, and small-scale trials using questionnaires and analysis, (4) revision of the first product design, based on the results of experts and small-scale trials (20 students), (5) field trials (48 students), (6) final product revision, (7) the final result of the modification produced through revision of field trials.The results of expert validation were carried out by 2 validities, namely validation in the field of athletic experts and validation of physical education material experts, and the results obtained in each validity were the first for the validation results in the field of athletic experts getting a percentage of 87.6% calcification (Good) , the second for the validation results in the field of Physical Education material experts got a percentage of 83.0% with the classification (Good). The results of the student questionnaire on a small scale test got a percentage of 86.6% (good). the results of the questionnaire on large-scale test students got a percentage of 81.8% (good).The conclusion and advice is that the development of a modified model of disc throwing tools with iron plate waste media can be used as an alternative to discus throwing. With the modification of disc throwing, teachers and students can be helped in learning discusses, students are interested and more active and excited in learning throw the disc.

scholarly journals Pengembangan Komik Matematika Berbasis Kontekstual Untuk Materi Lingkaran

2021 ◽  
Vol 3 (2) ◽  
pp. 55
Author(s):  
Elfrida Rif’atul Chusniah ◽  
Rini Setianingsih
Keyword(s):  
Research And Development ◽  
Teaching And Learning ◽  
Field Trials ◽  
Student Response ◽  
Quality Of Education ◽  
Small Scale ◽  
Maximum Score ◽  
Is Research ◽  
Scale Field

Penelitian ini adalah penelitian yang bertujuan untuk mengembangkan komik matematika berbasis kontekstual untuk materi lingkaran yang berkualitas baik berdasarkan tiga kriteria, yaitu valid, praktis, dan efektif. Rancangan penelitian ini adalah Research and Development (R&D). Prosedur-prosedur pengembangan yang digunakan meliputi empat langkah: (1) melakukan perencanaan produk yang akandikembangkan, (2) mengembangkan produk awal, (3) validasi dan revisi produk, (4) uji coba lapangan skala kecil dan revisi. Uji coba komik dilakukan secara terbatas oleh 10 siswa kelas VIII SMP. Teknik pengumpulan data yang diterapkan dalam penelitian ini adalah angket, sedangkan instrumen penelitian yangdigunakan meliputi lembar validasi, angket penggunaan media, dan angket respon siswa. Data penelitian dianalisis dengan deskriptif kualitatif. Hasil penelitian ini menunjukkan bahwa komik matematika dinyatakan valid dengan skor kevalidan 4 oleh ahli media dan 3,9 oleh ahli materi dari skor maksimum 5 sehingga dikategorikan valid, komik matematika dinyatakan praktis dengan hasil analisis persentase kepraktisan 76,28 % dan komik matematika dinyatakan efektif degan hasil analisis persentase keefektifan 79,4%, sehingga dikategorikan efektif. Berdasarkan hasil tersebut maka media komik ini memiliki kualitas yang baik sehingga dapat dimanfaatkan sebagai satu upaya atau alternatif media dalam proses pembelajaran sebagai upaya peningkatan kualitas pendidikan dan menciptakan suasana yang menyenangkan bagi siswa.Kata Kunci: media pembelajaran, komik matematika, lingkaranThis research is a research that aims to develop contextual based mathematical comics for good quality circle material based on three criteria, namely valid, practical, and effective. The design of this research is Research and Development (R&D). The development procedures used include four steps: (1) conducting product planning to be developed, (2) developing initial products, (3) product validation and revision, (4) small-scale field trials and revisions. Comic trials are limited to 10 students in grade VIII SMP. Data collection techniques applied in this study were questionnaires, while the research instruments used included validation sheets, media use questionnaires, and student response questionnaires. The research data were analyzed by descriptive qualitative. The results of this study indicate that mathematics comics are declared valid with a validity score of 4 by media experts and 3.9 by material experts from a maximum score of 5 so that they are categorized valid, mathematical comics are declared practical with the results of a practicality percentage analysis of 76.28% and mathematical comics are declared effective with the result of the analysis of the effectiveness percentage is 79.4%, so it is categorized as effective. Based on these results, this comic media has good quality so that it can be used as an alternative media used by teachers in the teaching and learning process in an effort to improve the quality of education and create a pleasant atmosphere for students.Keywords: learning media, mathematical comics, circles

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