scholarly journals Controlling invasive rodents via synthetic gene drive and the role of polyandry

2019 ◽  
Vol 286 (1909) ◽  
pp. 20190852 ◽  
Author(s):  
Andri Manser ◽  
Stephen J. Cornell ◽  
Andreas Sutter ◽  
Dimitri V. Blondel ◽  
Megan Serr ◽  
...  
Keyword(s):  
Target Population ◽  
Natural Setting ◽  
Pest Species ◽  
Gene Drive ◽  
Island Ecosystems ◽  
Control Programmes ◽  
Potential Pest ◽  
Invasive Rodents ◽  
Native Invasive

House mice are a major ecosystem pest, particularly threatening island ecosystems as a non-native invasive species. Rapid advances in synthetic biology offer new avenues to control pest species for biodiversity conservation. Recently, a synthetic sperm-killing gene drive construct called t-Sry has been proposed as a means to eradicate target mouse populations owing to a lack of females. A factor that has received little attention in the discussion surrounding such drive applications is polyandry. Previous research has demonstrated that sperm-killing drivers are extremely damaging to a male’s sperm competitive ability. Here, we examine the importance of this effect on the t-Sry system using a theoretical model. We find that polyandry substantially hampers the spread of t-Sry such that release efforts have to be increased three- to sixfold for successful eradication. We discuss the implications of our finding for potential pest control programmes, the risk of drive spread beyond the target population, and the emergence of drive resistance. Our work highlights that a solid understanding of the forces that determine drive dynamics in a natural setting is key for successful drive application, and that exploring the natural diversity of gene drives may inform effective gene drive design.

scholarly journals Gene drives and population persistence vs elimination: the impact of spatial structure and inbreeding at low density

2021 ◽  
Author(s):  
Pantelis John Beaghton ◽  
Austin Burt
Keyword(s):  
Inbreeding Depression ◽  
Essential Gene ◽  
Random Mating ◽  
Critical Role ◽  
Target Population ◽  
Low Density ◽  
Pest Species ◽  
Allee Effects ◽  
Gene Drive ◽  
The Impact

Synthetic gene drive constructs are being developed to control disease vectors, invasive species, and other pest species. In a well-mixed random mating population a sufficiently strong gene drive is expected to eliminate a target population, but it is not clear whether the same is true when spatial processes play a role. In species with an appropriate biology it is possible that drive-induced reductions in density might lead to increased inbreeding, reducing the efficacy of drive, eventually leading to suppression rather than elimination, regardless of how strong the drive is. To investigate this question we analyse a series of explicitly solvable stochastic models considering a range of scenarios for the relative timing of mating, reproduction, and dispersal and analyse the impact of two different types of gene drive, a Driving Y chromosome and a homing construct targeting an essential gene. We find in all cases a sufficiently strong Driving Y will go to fixation and the population will be eliminated, except in the one life history scenario (reproduction and mating in patches followed by dispersal) where low density leads to increased inbreeding, in which case the population persists indefinitely, tending to either a stable equilibrium or a limit cycle. These dynamics arise because Driving Y males have reduced mating success, particularly at low densities, due to having fewer sisters to mate with. Increased inbreeding at low densities can also prevent a homing construct from eliminating a population. For both types of drive, if there is strong inbreeding depression, then the population cannot be rescued by inbreeding and it is eliminated. These results highlight the potentially critical role that low-density-induced inbreeding and inbreeding depression (and, by extension, other sources of Allee effects) can have on the eventual impact of a gene drive on a target population.

scholarly journals Double drives and private alleles for localised population genetic control

PLoS Genetics ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. e1009333
Author(s):  
Katie Willis ◽  
Austin Burt
Keyword(s):  
Genetic Control ◽  
Population Genetic ◽  
Genomic Analysis ◽  
Target Population ◽  
Pest Species ◽  
Gene Drive ◽  
Population Replacement ◽  
Target Populations ◽  
Control Disease ◽  
Alternative Designs

Synthetic gene drive constructs could, in principle, provide the basis for highly efficient interventions to control disease vectors and other pest species. This efficiency derives in part from leveraging natural processes of dispersal and gene flow to spread the construct and its impacts from one population to another. However, sometimes (for example, with invasive species) only specific populations are in need of control, and impacts on non-target populations would be undesirable. Many gene drive designs use nucleases that recognise and cleave specific genomic sequences, and one way to restrict their spread would be to exploit sequence differences between target and non-target populations. In this paper we propose and model a series of low threshold double drive designs for population suppression, each consisting of two constructs, one imposing a reproductive load on the population and the other inserted into a differentiated locus and controlling the drive of the first. Simple deterministic, discrete-generation computer simulations are used to assess the alternative designs. We find that the simplest double drive designs are significantly more robust to pre-existing cleavage resistance at the differentiated locus than single drive designs, and that more complex designs incorporating sex ratio distortion can be more efficient still, even allowing for successful control when the differentiated locus is neutral and there is up to 50% pre-existing resistance in the target population. Similar designs can also be used for population replacement, with similar benefits. A population genomic analysis of CRISPR PAM sites in island and mainland populations of the malaria mosquitoAnopheles gambiaeindicates that the differentiation needed for our methods to work can exist in nature. Double drives should be considered when efficient but localised population genetic control is needed and there is some genetic differentiation between target and non-target populations.

Invasive forest pest surveillance: survey development and reliability

2008 ◽  
Vol 38 (9) ◽  
pp. 2422-2433 ◽  
Author(s):  
John W. Coulston ◽  
Frank H. Koch ◽  
William D. Smith ◽  
Frank J. Sapio
Keyword(s):  
Statistical Power ◽  
Sampling Technique ◽  
Cost Effective ◽  
The United States ◽  
Invasive Pest ◽  
Pest Species ◽  
Forest Pest ◽  
Forested Landscapes ◽  
Potential Pest ◽  
Native Invasive

Worldwide, a large number of potential pest species are introduced to locations outside their native ranges; under the best possible prevention scheme, some are likely to establish one or more localized populations. A comprehensive early detection and rapid-response protocol calls for surveillance to determine if a pest has invaded additional locations outside its original area of introduction. In this manuscript, we adapt and spatially extend a two-stage sampling technique to determine the required sample size to substantiate freedom from an invasive pest with a known level of certainty. The technique, derived from methods for sampling livestock herds for disease presence, accounts for the fact that pest activity may be low at a coarse spatial scale (i.e., among forested landscapes) but high at a fine scale (i.e., within a given forested landscape). We illustrate the utility of the approach by generating a national-scale survey based on a risk map for a hypothetical forest pest species threatening the United States. These techniques provide a repeatable, cost-effective, practical framework for developing broad-scale surveys to substantiate freedom from non-native invasive forest pests with known statistical power.

scholarly journals Double drives and private alleles for localised population genetic control

2021 ◽  
Author(s):  
Katie Willis ◽  
Austin Burt
Keyword(s):  
Genetic Control ◽  
Population Genetic ◽  
Genomic Analysis ◽  
Target Population ◽  
Pest Species ◽  
Gene Drive ◽  
Population Replacement ◽  
Target Populations ◽  
Mosquito Anopheles Gambiae ◽  
Control Disease

Synthetic gene drive constructs could, in principle, provide the basis for highly efficient interventions to control disease vectors and other pest species. This efficiency derives in part from leveraging natural processes of dispersal and gene flow to spread the construct and its impacts from one population to another. However, sometimes (for example, with invasive species) only specific populations are in need of control, and impacts on non-target populations would be undesirable. Many gene drive designs use nucleases that recognise and cleave specific genomic sequences, and one way to restrict their spread would be to exploit sequence differences between target and non-target populations. In this paper we propose and model a series of low threshold double drive designs for population suppression, each consisting of two constructs, one imposing a reproductive load on the population and the other inserted into a differentiated locus and controlling the drive of the first. Simple deterministic, discrete-generation computer simulations are used to assess the alternative designs. We find that the simplest double drive designs are significantly more robust to pre-existing cleavage resistance at the differentiated locus than single drive designs, and that more complex designs incorporating sex ratio distortion can be more efficient still, even allowing for successful control when the differentiated locus is neutral and there is up to 50% pre-existing resistance in the target population. Similar designs can also be used for population replacement, with similar benefits. A population genomic analysis of PAM sites in island and mainland populations of the malaria mosquito Anopheles gambiae indicates that the differentiation needed for our methods to work can exist in nature. Double drives should be considered when efficient but localised population genetic control is needed and there is some genetic differentiation between target and non-target populations.

scholarly journals Evaluation of the Effectiveness of Brazilian Community Restaurants for the Dimension of Low-Income People Access to Food

Nutrients ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 2671
Author(s):  
Mateus Santana Sousa ◽  
Camila Silveira Silva Teixeira ◽  
Jamacy Costa Souza ◽  
Priscila Ribas de Farias Costa ◽  
Renata Puppin Zandonadi ◽  
...  
Keyword(s):  
Low Income ◽  
Formal Education ◽  
Average Energy ◽  
Secondary Data ◽  
Target Population ◽  
Service Capacity ◽  
The Public ◽  
The Government ◽  
Access To Food

This study aimed to evaluate the effectiveness of community restaurants (CRs), managed by the Government of the State of Bahia/Brazil, for the dimension of access to food. The study used secondary data obtained from the public opinion survey Profile of users of community restaurants in Salvador. The nutritional information was accessed through the analysis of CRs’ menus. Adequate effectiveness of access to food was considered when the CR served meals to 50% to 70% of the users considered the target audience (individuals served by the two CRs located in the city of Salvador/Bahia/Brazil). The participants (n = 1464; 778 as low-income individuals) were adult CR users from Salvador/Brazil. Most of the respondents were male, 40 to 54 years old, not white, had up to 9 years of formal education, without a partner, and living in the municipality of Salvador. The evaluated CRs are effective in serving 53.1% of the target population in their total service capacity. Meal provision only reached an estimated 0.7% of the socially vulnerable community in the district. The average energy value of the meal served by the CR units was 853.05 kcal/meal, with a mean energy density composition classified as average (1.15 kcal/g). The effectiveness of the evaluated community restaurants showed that these instruments were minimally effective in promoting access to food for the low-income population within their total daily service capacity, and the current quantity of these facilities was insufficient. However, these instruments stand out in the fundamental role of promoting the daily distribution of meals to the Brazilian population with the highest social vulnerability levels.

scholarly journals THE ROLE OF HEALTH LITERACY ON PROCESS AND OUTCOMES OF A DIABETES SELF-HELP INTERVENTION WITH KOREAN AMERICANS

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S406-S406
Author(s):  
Miyong T Kim
Keyword(s):  
Health Literacy ◽  
Glucose Control ◽  
Self Efficacy ◽  
Diabetes Management ◽  
Self Care ◽  
Korean Americans ◽  
Target Population ◽  
Management Intervention ◽  
Underlying Mechanisms

Abstract The purpose of this study was to explicate the underlying mechanisms of the role of health literacy (HL) in diabetes management process involving a group of Korean Americans with type 2 diabetes mellitus (DM). We used data from a randomized clinical trial of an HL-focused diabetes self-management intervention (n = 250). A series of path analyses identified the level of self-efficacy and self-care skills as a significant mediator between HL and glucose control (HbA1C) and quality of life for the target population. In addition, education and acculturation were revealed as the most significant correlates of HL for this new immigrant group. Despite inconsistent empirical findings regarding the statistically significant effect of HL on glucose control, this study confirmed the apriority hypothesis that HL indirectly influences health outcome through mediators such self-care skills as self-efficacy. This study highlighted the importance of HL in chronic disease management for people with limited HL.

scholarly journals Role of Context, Resources, and Target Population in the Fidelity of Critical Time Intervention

2016 ◽  
Vol 67 (1) ◽  
pp. 115-118 ◽  
Author(s):  
Stacey L. Barrenger ◽  
Liat S. Kriegel ◽  
Beth Angell ◽  
Jeffrey Draine
Keyword(s):  
Critical Time ◽  
Target Population ◽  
Critical Time Intervention

scholarly journals Percepción de los entrenadores de alto rendimiento de atletismo: caracterización de su perfil polifacético (Perception of high performance track and field coaches: characterization of their multifaceted profile)

Retos ◽  
2015 ◽  
pp. 42-47
Author(s):  
Angeles Filgueira Perez
Keyword(s):  
High Performance ◽  
Target Population ◽  
Track And Field ◽  
Personal Qualities ◽  
High Level ◽  
Almost All ◽  
Methodological Aspects ◽  
The Ideal

En el presente estudio se ha tratado de obtener una aproximación al perfil ideal del entrenador de alto rendimiento en atletismo. En el mundo del deporte de alta competición, el entrenador debe desarrollar funciones de maestro, técnico y líder, lo cual hace difícil delimitar sus competencias (conocimientos, habilidades y cualidades personales). Por tanto, la principal motivación de este trabajo es establecer el papel que debe desempeñar el entrenador para la preparación física, técnica, táctica, psicológica y moral del deportista de alto nivel. Para ello, se ha considerado como población objeto de estudio al conjunto de entrenadores de alto rendimiento que en el momento de la investigación estuviesen activo, ya que interesaba realizar este estudio desde su propia perspectiva. Los datos recogidos forman parte de una investigación más amplia, llevada a cabo mediante encuesta, para la que se diseñó un cuestionario de 78 preguntas en el que se abarcaban tres temas: el perfil del entrenador y del deportista, así como la figura del formador de entrenadores en el Practicum. En este trabajo nos centramos en el primer tema y el análisis de la información obtenida nos permite concluir que la que práctica totalidad de los entrenadores de atletismo consideran necesario dominar con precisión los aspectos técnico-metodológicos. Además, consideran que su ética profesional debe estar regida por los principios de autonomía y beneficencia, de modo que valores como la honestidad y la justicia deben primar en el desarrollo de sus funciones.Abstract: In the current study, we have tried to get an approximation of the ideal profile of high performance coaches in athletics. In the high-level sports world, the coach must develop the role of teacher, technician and leader,  which makes it difficult to delimit  his/her competencies (knowledge, skills and personal qualities). Therefore, the main motivation of this work is to define the role that the coach plays in relation  to the physical, technical, tactical, psychological and moral preparation of elite athletes. Keeping this aim as an objective, we have considered as the target population the high performance coaches who are active at the time of the investigation, since we were interested  in knowing their own perspective. The data that was collected is a part of a wider investigation, conducted by a survey, for which we designed a questionnaire of 78 questions divided on three topics: the profile of the coach and the athlete, as well as the figure of the coach educator in the Practicum. In this work, we focus on the first topic and the analysis of the information that we obtained allows us to conclude that almost all the track and field coaches find it necessary to dominate the technical and methodological aspects. They also consider that professional ethics must be governed by the principles of autonomy and care that values   like honesty and justice must prevail in the performance of their work.

Sign in / Sign up

Export Citation Format

Share Document