Keywords: Modeling

Overcoming drug-resistant tumors with selection gene drives

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Hui Wang, Mingqi Xie,  Cell Genomics,  4. 2024.
Drug resistance is a major hurdle prohibiting effective treatment of many diseases, including cancer. Using model-guided designs, Leighow et al.1 engineered a dual-switch selection gene drive system custom designed to combat drug-resistant tumors. By demonstrating remarkable ...

Applications of Mathematical Programming to Genetic Biocontrol

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Váleri N. Vásquez, John M. Marshall,  SIAM Journal on Applied Mathematics,  84. 2024.
We review existing approaches to optimizing the deployment of genetic biocontrol technologies—tools used to prevent vector-borne diseases such as malaria and dengue—and formulate a mathematical program that enables the incorporation of crucial ecological and logistical ...

Population suppression with dominant female-lethal alleles is boosted by homing gene drive

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Zhu, J., Chen, J., Liu, Y. et al.,  BMC Biology,  22. 2024.
Methods to suppress pest insect populations using genetic constructs and repeated releases of male homozygotes have recently been shown to be an attractive alternative to older sterile insect techniques based on radiation. Female-specific lethal alleles have substantially ...

Deployment of tethered gene drive for confined suppression in continuous space requires avoiding drive wave interference

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Ruobing Feng, Jackson Champer,  Molecular Ecology,  33. 2024.
Gene drives have great potential for suppression of pest populations and removal of exotic invasive species. CRISPR homing suppression drive is a powerful but unconfined drive, posing risks of uncontrolled spread. Thus, developing methods for confining a gene drive is of great ...

Population suppression by release of insects carrying a dominant sterile homing gene drive targeting doublesex in Drosophila

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Chen, W., Guo, J., Liu, Y. et al.,  Nature Communications,  15:8053. 2024.
CRISPR homing gene drives can suppress pest populations by targeting female fertility genes, converting wild-type alleles into drive alleles in the germline of drive heterozygotes. fsRIDL (female-specific Release of Insects carrying a Dominant Lethal) is a self-limiting ...

Altering traits and fates of wild populations with Mendelian DNA sequence modifying Allele Sails

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Michelle L. Johnson, Bruce A. Hay, Maciej Maselko,  Nature Communications,  15. 2024.
Population-scale genome editing can be used to alter the composition or fate of wild populations. One approach to achieving these aims utilizes a synthetic gene drive element—a multi-gene cassette—to bring about an increase in the frequency of an existing allele. However, the ...

Incorporating ecology into gene drive modelling

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J. Kim, K. D. Harris, I. K. Kim, S. Shemesh, P. W. Messer and G. Greenbaum,  Ecology Letters,  26:S62-S80. 2023.
Abstract Gene drive technology, in which fast-spreading engineered drive alleles are introduced into wild populations, represents a promising new tool in the fight against vector-borne diseases, agricultural pests and invasive species. Due to the risks involved, gene drives have ...

Expansions to the MGDrivE suite for simulating the efficacy of novel gene-drive constructs in the control of mosquito-borne diseases

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J. B. Bennett, S. L. Wu, P. R. Chennuri, K. M. Myles and M. L. Ndeffo-Mbah,  BMC Research Notes,  16:258. 2023.
The MGDrivE (MGDrivE 1 and MGDrivE 2) modeling framework provides a flexible and expansive environment for testing the efficacy of novel gene-drive constructs for the control of mosquito-borne diseases. However, the existing model framework did not previously support several ...

MGDrivE 3: A decoupled vector-human framework for epidemiological simulation of mosquito genetic control tools and their surveillance

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A. Mondal, C. H. M. Sanchez and J. M. Marshall,  bioRxiv,  2023.09.09.556958. 2023.
We present MGDrivE 3 (Mosquito Gene Drive Explorer 3), a new version of a previously-developed framework, MGDrivE 2, that investigates the spatial population dynamics of mosquito genetic control systems and their epidemiological implications. The new framework incorporates three ...

Making waves: Comparative analysis of gene drive spread characteristics in a continuous space model

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Pan, Mingzuyu Champer, Jackson,  Molecular Ecology,  2023.
Abstract With their ability to rapidly increase in frequency, gene drives can be used to modify or suppress target populations after an initial release of drive individuals. Recent advances have revealed many possibilities for different types of drives, and several of these have ...

A migration-selection model in genetic engineering

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Y. Qi and L. Su,  Nonlinear Analysis: Real World Applications,  75:103983. 2023.
We investigate a migration-selection system arising from CRISPR-Cas9 genetic engineering, which describes the evolution of the frequencies of a wild allele O, a drive allele D, and a brake allele B. The purpose is to see whether the drive allele D can persist in the population ...

Female meiotic drive shapes the distribution of rare inversion polymorphisms in Drosophila melanogaster

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S. A. Koury,  Genetics,  2023.
In all species, new chromosomal inversions are constantly being formed by spontaneous rearrangement and then stochastically eliminated from natural populations. In Drosophila, when new chromosomal inversions overlap with a pre-existing inversion in the population, their rate of ...

Gene drives for invasive wasp control: Extinction is unlikely, with suppression dependent on dispersal and growth rates

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P. J. Lester, D. O'Sullivan and G. L. W. Perry,  Ecological Applications,  2023.
Abstract Gene drives offer a potentially revolutionary method for pest control over large spatial extents. These genetic modifications spread deleterious variants through a population and have been proposed as methods for pest suppression or even eradication. We examined the ...

The impact of predators of mosquito larvae on Wolbachia spreading dynamics

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Z. Zhu, Y. Hui and L. Hu,  Journal of Biological Dynamics,  17:2249024. 2023.
Dengue fever creates more than 390 million cases worldwide yearly. The most effective way to deal with this mosquito-borne disease is to control the vectors. In this work we consider two weapons, the endosymbiotic bacteria Wolbachia and predators of mosquito larvae, for combating ...

Optimizing the delivery of self-disseminating vaccines in fluctuating wildlife populations

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C. Schreiner, A. Basinski, C. Remien and S. Nuismer,  PLOS Neglected Tropical Diseases,  17:e0011018. 2023.
Author summary Pathogens such as Ebola, rabies, and Lassa virus that usually infect wildlife can jump to the human population. In the worst case, this can lead to outbreaks or pandemics such as happened in 2014 with Ebola and 2019 with SARS-CoV-2. One approach to mitigate the ...

Modeling the Impact of Migration on Mosquito Population Suppression

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M. Huang and J. Yu,  Qualitative Theory of Dynamical Systems,  22:134. 2023.
The Wolbachia-induced incompatible insect technique is a promising strategy for controlling wild mosquito populations. However, recent experimental studies have shown that mosquito migration into target areas dilutes the strategy’s effectiveness. In this work, we formulate a ...

Pulled, pushed or failed: the demographic impact of a gene drive can change the nature of its spatial spread

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L. Kläy, L. Girardin, V. Calvez and F. Débarre,  Journal of Mathematical Biology,  87:30. 2023.
Understanding the temporal spread of gene drive alleles-alleles that bias their own transmission-through modeling is essential before any field experiments. In this paper, we present a deterministic reaction-diffusion model describing the interplay between demographic and allelic ...

Estimating mosquito abundance and population suppression in an incompatible insect technique study

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L. Griffin, D. Pagendam, C. Drovandi, B. Trewin and N. W. Beebe,  Journal of Applied Ecology,  2023.
Our model can provide valuable insights that can shape decision support systems in sterile insect technique and incompatible insect technique programmes operating over large geographical scales. The model helps determine how many sterile/incompatible insects should be released ...

Threshold dynamics of a stochastic mathematical model for Wolbachia infections

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J. Yang, Z. Chen, Y. Tan, Z. Liu and R. A. Cheke,  Journal of Biological Dynamics,  17:2231967. 2023.
A stochastic mathematical model is proposed to study how environmental heterogeneity and the augmentation of mosquitoes with Wolbachia bacteria affect the outcomes of dengue disease. The existence and uniqueness of the positive solutions of the system are studied. Then the ...

MGSurvE: A framework to optimize trap placement for genetic surveillance of mosquito population

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C. H. Sánchez, D. L. Smith and J. M. Marshall,  bioRxiv,  2023.
Genetic surveillance of mosquito populations is becoming increasingly relevant as genetics-based mosquito control strategies advance from laboratory to field testing. Especially applicable are mosquito gene drive projects, the potential scale of which leads monitoring to be a ...

Modeling emergence of Wolbachia toxin-antidote protein functions with an evolutionary algorithm

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J. Beckmann, J. Gillespie and D. Tauritz,  Front Microbiol,  14:1116766. 2023.
Evolutionary algorithms (EAs) simulate Darwinian evolution and adeptly mimic natural evolution. Most EA applications in biology encode high levels of abstraction in top-down population ecology models. In contrast, our research merges protein alignment algorithms from ...

The optimal strategy of incompatible insect technique (IIT) using Wolbachia and the application to malaria control

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T. Matsufuji and S. Seirin-Lee,  Journal of Theoretical Biology,  569:111519. 2023.
For decades, techniques to control vector population with low environmental impact have been widely explored in both field and theoretical studies. The incompatible insect technique (IIT) using Wolbachia, based on cytoplasmic incompatibility, is a technique that ...

Leveraging eco-evolutionary models for gene drive risk assessment

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M. A. Combs, A. J. Golnar, J. M. Overcash, A. L. Lloyd, K. R. Hayes, D. A. O’Brochta and K. M. Pepin,  Trends in Genetics,  2023.
As development of gene drive systems accelerates and diversifies, predicting outcomes for target populations and the potential for human and environmental risks requires accounting for numerous eco-evolutionary processes.Gene drive dynamic models quantify the influence of ...

Leveraging eco-evolutionary models for gene drive risk assessment

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M. A. Combs, A. J. Golnar, J. M. Overcash, A. L. Lloyd, K. R. Hayes, D. A. O’Brochta and K. M. Pepin,  Trends in Genetics,  2023.
As development of gene drive systems accelerates and diversifies, predicting outcomes for target populations and the potential for human and environmental risks requires accounting for numerous eco-evolutionary processes.Gene drive dynamic models quantify the influence of ...

Adversarial interspecies relationships facilitate population suppression by gene drive in spatially explicit models

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Y. Liu, W. Teo, H. Yang and J. Champer,  Ecology Letters,  2023.
Abstract Suppression gene drives bias their inheritance to spread through a population, potentially eliminating it when they reach high frequency. CRISPR homing suppression drives have already seen success in the laboratory, but several models predict that success may be elusive ...

Mathematical modeling of the performance of wild and transgenic mosquitoes in malaria transmission

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A. P. Wyse, A. J. B. dos Santos, J. D. Azevedo, A. C. de Meneses and V. M. D. Santos,  Plos One,  18:23. 2023.
A mathematical model that simulates malaria transmission under the influence of transgenic mosquitoes refractory to malaria is presented in this paper. The zygosity of transgenic mosquitoes is taken into account and, consequently, the total population of mosquitoes is comprised ...

Modelling the effect of migration on the localisation and spread of a gene drive

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C. Benjamin James and F.-L. Alexandre Jules Hen,  bioRxiv,  2023.04.02.535303. 2023.
Gene drives have the potential to address pressing ecological issues. Through the super-Mendelian inheritance of a gene drive, a trait can be spread through a population even in spite of a fitness cost. This ability to spread is both its greatest quality and detractor. We may not ...

Modelling the effect of migration on the localisation and spread of a gene drive

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C. Benjamin and F.-L. Alexandre,  bioRxiv,  2023.
Gene drives have the potential to address pressing ecological issues. Through the super-Mendelian inheritance of a gene drive, a trait can be spread through a population even in spite of a fitness cost. This ability to spread is both its greatest quality and detractor. We may not ...

Modelling Emergence of Wolbachia Toxin-Antidote Protein Functions with an Evolutionary Algorithm

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J. Beckmann, J. Gillespie and D. Tauritz,  bioRxiv,  2023.
Evolutionary algorithms (EAs) simulate Darwinian evolution and adeptly mimic natural evolution. Most EA applications in biology encode high levels of abstraction in top-down ecological population models. In contrast, our research merges protein alignment algorithms from ...

Modeling Sustained Transmission of Wolbachia among Anopheles Mosquitoes: Implications for Malaria Control in Haiti

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D. Florez, A. J. Young, K. J. Bernabé, J. M. Hyman and Z. Qu,  Trop Med Infect Dis,  8. 2023.
Wolbachia infection in Anopheles albimanus mosquitoes can render mosquitoes less capable of spreading malaria. We developed and analyzed a mechanistic compartmental ordinary differential equation model to evaluate the effectiveness of Wolbachia-based vector control strategies ...

A mosquito population suppression model with a saturated Wolbachia release strategy in seasonal succession

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Z. Zhang, L. Chang, Q. Huang, R. Yan and B. Zheng,  J Math Biol,  86:51. 2023.
Releasing Wolbachia-infected male mosquitoes to suppress wild female mosquitoes through cytoplasmic incompatibility has shown great promise in controlling and preventing mosquito-borne diseases. To make the release logistically and economically feasible, we propose a saturated ...

Hybrid incompatibilities in the anopheles gambiae species complex

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A. Kriezis,  Imperial College London,  2023.
Malaria is an infectious disease caused by parasites of the genus Plasmodium which is responsible for approximately 400,000 deaths annually, primarily in sub-Saharan Africa. Malaria is transmitted by mosquitoes belonging to the Anopheles gambiae species complex. While progress ...

Simulations Reveal High Efficiency and Confinement of a Population Suppression CRISPR Toxin-Antidote Gene Drive

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Y. Zhu and J. Champer,  ACS Synthetic Biolog,  2023.
Though engineered gene drives hold great promise for spreading through and suppressing populations of disease vectors or invasive species, complications such as resistance alleles and spatial population structure can prevent their success. Additionally, most forms of suppression ...

Review of gene drive modelling and implications for risk assessment of gene drive organisms

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J. L. Frieß, C. R. Lalyer, B. Giese, S. Simon and M. Otto,  Ecological Modelling,  478:110285. 2023.
Synthetic gene drive (GD) systems constitute a form of novel invasive environmental biotechnology with far-reaching consequences beyond those of other known genetically modified organisms (GMOs). During the last 10 years, the development of GD systems has been closely linked to ...

Harnessing Wolbachia cytoplasmic incompatibility alleles for confined gene drive: A modeling study

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J. Li and J. Champer,  PLOS Genetics,  19:e1010591. 2023.
Wolbachia are maternally-inherited bacteria, which can spread rapidly in populations by manipulating reproduction. cifA and cifB are genes found in Wolbachia phage that are responsible for cytoplasmic incompatibility, the most common type of Wolbachia reproductive interference. ...

Dynamics of an impulsive reaction-diffusion mosquitoes model with multiple control measures

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Y. Li, H. Zhao and K. Wang,  Mathematical Biosciences and Engineering,  20:775-806. 2023.
It is well-known that mosquito control is one of the effective methods to reduce and prevent the transmission of mosquito-borne diseases. In this paper, we formulate a reaction-diffusion impulsive hybrid model incorporating Wolbachia, impulsively spraying of insecticides, spatial ...

Gene drive designs for efficient and localisable population suppression using Y-linked editors

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R. Geci, K. Willis and A. Burt,  PLOS Genetics,  18:e1010550. 2022.
Author summary Some pest populations can be successfully controlled by the inundative release of sterile males, but this approach is not practicable when the target population is large or the species difficult to rear. Computer modelling has previously demonstrated that releasing ...

Performance characteristics allow for confinement of a CRISPR toxin-antidote gene drive designed for population suppression

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S. Zhang and J. Champer,  bioRxiv,  2022.12.13.520356. 2022.
Gene drives alleles that can bias their own inheritance are a promising way to engineer populations for control of disease vectors, invasive species, and agricultural pests. Recent advancements in the field have yielded successful examples of powerful suppression type drives and ...

Tolerance-conferring defensive symbionts and the evolution of parasite virulence

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C. A. Smith and B. Ashby,  bioRxiv,  2022.
Defensive symbionts in the host microbiome can confer protection from infection or reduce the harms of being infected by a parasite. Defensive symbionts are therefore promising agents of biocontrol that could be used to control or ameliorate the impact of infectious diseases. ...

Rescue by gene swamping as a gene drive deployment strategy

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K. D. Harris and G. Greenbaum,  bioRxiv,  2022.03.08.483503. 2022.
Gene drives are genetic constructs that can spread deleterious alleles with potential application to population suppression of harmful species. Given that a gene drive can potentially spill over to other populations or even other species, control measures and fail-safes ...

Modeling-informed Engineered Genetic Incompatibility strategies to overcome resistance in the invasive Drosophila suzukii

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A. Sychla, N. R. Feltman, W. D. Hutchison and M. J. Smanski,  Frontiers in Insect Science,  2. 2022.
Engineered Genetic Incompatibility (EGI) is an engineered extreme underdominance genetic system wherein hybrid animals are not viable, functioning as a synthetic speciation event. There are several strategies in which EGI could be leveraged for genetic biocontrol of pest ...

The effect of mating complexity on gene drive dynamics

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P. Verma, R. G. Reeves, S. Simon, M. Otto and C. S. Gokhale,  The American Naturalist,  2022.
Gene drive technology promises to deliver on some of the global challenges humanity faces today in health care, agriculture, and conservation. However, there is a limited understanding of the consequences of releasing self-perpetuating transgenic organisms into wild populations ...

Gene drive technology to suppress invasive mice

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University of Adelaide,  Phys Org,  2022.
Researchers at the University of Adelaide have released their first findings on the potential effectiveness of revolutionary gene drive technology to control invasive mice. The team has developed a world-first proof of concept for the technology—called t-CRISPR—using ...

Leveraging a natural murine meiotic drive to suppress invasive populations

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L. Gierus, A. Birand, M. D. Bunting, G. I. Godahewa, S. G. Piltz, K. P. Oh, A. J. Piaggio, D. W. Threadgill, J. Godwin, O. Edwards, P. Cassey, J. V. Ross, T. A. A. Prowse and P. Q. Thomas,  Proceedings of the National Academy of Sciences,  119:e2213308119. 2022.
Invasive rodents are a major cause of environmental damage and biodiversity loss, particularly on islands. Unlike insects, genetic biocontrol strategies including population-suppressing gene drives with biased inheritance have not been developed in mice. Here, we demonstrate a ...

Making waves: Comparative analysis of gene drive spread characteristics in a continuous space model

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M. Pan and J. Champer,  bioRxiv,  2022.11.01.514650. 2022.
With their ability to rapidly increase in frequency, gene drives can be used to modify or suppress target populations after an initial release of drive-containing individuals. Recent advances in this field have revealed many possibilities for different types of drives, and ...

Modeling the efficacy of CRISPR gene drive for snail immunity on schistosomiasis control

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R. E. Grewelle, J. Perez-Saez, J. Tycko, E. K. O. Namigai, C. G. Rickards and G. A. De Leo,  PLOS Neglected Tropical Diseases,  16:e0010894. 2022.
CRISPR gene drives could revolutionize the control of infectious diseases by accelerating the spread of engineered traits that limit parasite transmission in wild populations. Gene drive technology in mollusks has received little attention despite the role of freshwater snails as ...

Monotonicity properties arising in a simple model of Wolbachia invasion for wild mosquito populations

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D. Vicencio, O. Vasilieva and P. Gajardo,  Mathematical Biosciences and Engineering,  20:1148-1175. 2022.
Using tools borrowed from monotone dynamical system theory, in the proposed model, we prove the existence of an invariant threshold manifold that allows us to provide practical recommendations for performing single and periodic releases of Wolbachia-carrying mosquitoes, seeking ...

Pulled, pushed or failed: the demographic impact of a gene drive can change the nature of its spatial spread

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L. Kläy, L. Girardin, V. Calvez and F. Débarre,  arXiv,  2022.
Understanding the temporal spread of gene drive alleles -- alleles that bias their own transmission -- through modeling is essential before any field experiments. In this paper, we present a deterministic reaction-diffusion model describing the interplay between demographic and ...

Anopheles homing suppression drive candidates exhibit unexpected performance differences in simulations with spatial structure

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S. E. Champer, I. K. Kim, A. G. Clark, P. W. Messer and J. Champer,  eLife,  11:e79121. 2022.
Recent experiments have produced several Anopheles gambiae homing gene drives that disrupt female fertility genes, thereby eventually inducing population collapse. Such drives may be highly effective tools to combat malaria. One such homing drive, based on the zpg promoter ...

Externalities modulate the effectiveness of the Wolbachia release programme

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E. E. Ooi and A. Wilder-Smith,  The Lancet Infectious Diseases,  2022.
Despite the remarkable outcome in Yogyakarta, the wMel approach also has some challenges. In particular, the extent to which ecological, weather, and other external factors influence the dissemination and establishment of wMel in complex urban environments remains unclear. ...

Estimating the effect of the wMel release programme on the incidence of dengue and chikungunya in Rio de Janeiro, Brazil: a spatiotemporal modelling study

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G. Ribeiro dos Santos, B. Durovni, V. Saraceni, T. I. Souza Riback, S. B. Pinto, K. L. Anders, et al.,  The Lancet Infectious Diseases,  2022.
Summary Background Introgression of genetic material from species of the insect bacteria Wolbachia into populations of Aedes aegypti mosquitoes has been shown in randomised and non-randomised trials to reduce the incidence of dengue; however, evidence for the real-world ...

Daisy-chain gene drives: The role of low cut-rate, resistance mutations, and maternal deposition

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S. A. N. Verkuijl, M. A. E. Anderson, L. Alphey and M. B. Bonsall,  PLOS Genetics,  18:e1010370. 2022.
Author summary Reducing the harm of pest species by the introgression of traits into a wild population is often limited by the difficulties of mass rearing and release of modified individuals. Gene drives present an opportunity to substantially reduce the release frequencies ...

An optimal control problem for dengue transmission model with Wolbachia and vaccination

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J. Zhang, L. L. Liu, Y. Z. Li and Y. Wang,  Communications In Nonlinear Science and Numerical Simulation,  116. 2022.
The release of Wolbachia-infected mosquitoes into the wild mosquitoes population is an excellent biological control strategy which can be effective against mosquito-borne infections. In this work, we propose a dengue transmission model that incorporates releasing Wolbachia into ...

A confinable female-lethal population suppression system in the malaria vector, Anopheles gambiae

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A. L. Smidler, J. J. Pai, R. A. Apte, H. M. Sánchez C, R. M. Corder, E. J. Gutiérrez, N. Thakre, I. Antoshechkin, J. M. Marshall and O. S. Akbari,  bioRxiv,  2022.08.30.505861. 2022.
Malaria is among the world’s deadliest diseases, predominantly affecting sub-Saharan Africa, and killing over half a million people annually. Controlling the principal vector, the mosquito Anopheles gambiae, as well as other anophelines, is among the most effective methods to ...

Environmentally appropriate vector control is facilitated by standard metrics for simulation-based evaluation

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V. N. Vásquez, M. R. Reddy and J. M. Marshall,  Frontiers in Tropical Diseases,  3. 2022.
As anthropogenic factors contribute to the introduction and expansion of new and established vector species, the geographic incidence of mosquito-borne disease is shifting. Computer simulations, informed by field data where possible, facilitate the cost-effective evaluation of ...

Harnessing Wolbachia cytoplasmic incompatibility alleles for confined gene drive: a modeling study

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J. Li and J. Champer,  bioRxiv,  2022.08.09.503337. 2022.
By using both mathematical and simulation models, we found that a drive containing CifA and CifB together create a confined drive with a moderate to high introduction threshold. When introduced separately, they act as a self-limiting drive. We observed that the performance of ...

Wolbachia Dynamics in Mosquitoes with Incomplete CI and Imperfect Maternal Transmission by a DDE System

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Y. Su, B. Zheng and X. Zou,  Bulletin of Mathematical Biology,  84:95. 2022.
In this paper, we propose a delay differential equation model to describe the Wolbachia infection dynamics in mosquitoes in which the key factor of cytoplasmic incompactibility (CI) is incorporated in a more natural way than those in the literature. By analyzing the dynamics of ...

A theory of resistance to multiplexed gene drive demonstrates the significant role of weakly deleterious natural genetic variation

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B. S. Khatri and A. Burt,  Proceedings of the National Academy of Sciences,  119:e2200567119. 2022.
CRISPR-based gene drives have the potential for controlling natural populations of disease vectors, such as malaria-carrying mosquitoes in sub-Saharan Africa. If successful, they hold promise of significantly reducing the burden of disease and death from malaria and many other ...

Robust control strategy by the Sterile Insect Technique for reducing epidemiological risk in presence of vector migration

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P.-A. Bliman and Y. Dumont,  Mathematical Biosciences,  350:108856. 2022.
The Sterile Insect Technique (SIT) is a promising technique to control mosquitoes, vectors of diseases, like dengue, chikungunya or Zika. However, its application in the field is not easy, and its success hinges upon several constraints, one of them being that the treated area ...

Population replacement gene drive characteristics for malaria elimination in a range of seasonal transmission settings: a modelling study

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S. Leung, N. Windbichler, E. A. Wenger, C. A. Bever and P. Selvaraj,  Malaria Journal,  21:226. 2022.
BACKGROUND: Gene drives are a genetic engineering method where a suite of genes is inherited at higher than Mendelian rates and has been proposed as a promising new vector control strategy to reinvigorate the fight against malaria in sub-Saharan Africa. METHODS: Using an ...

Adaptive meiotic drive in selfing populations with heterozygote advantage

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E. Brud,  Theoretical Population Biology,  146:61-70. 2022.
The egalitarian allotment of gametes to each allele at a locus (Mendel's law of segregation) is a near-universal phenomenon characterizing inheritance in sexual populations. As exceptions to Mendel's law are known to occur, one can investigate why non-Mendelian segregation is not ...

Scalability of genetic biocontrols for eradicating invasive alien mammals

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A. Birand, P. Cassey, J. V. Ross, P. Q. Thomas and T. A. A. Prowse,  NeoBiota,  74:93-103. 2022.
CRISPR-based gene drives offer novel solutions for controlling invasive alien species, which could ultimately extend eradication efforts to continental scales. Gene drives for suppressing invasive alien vertebrates are now under development. Using a landscape-scale ...

Slow and steady wins the race: spatial and stochastic processes and the failure of suppression gene drives

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J. F. Paril and B. L. Phillips,  Molecular Ecology,  2022.
Gene drives that skew sex ratios offer a new management tool to suppress or eradicate pest populations. Early models and empirical work suggest that these suppression drives can completely eradicate well-mixed populations, but models that incorporate stochasticity and space ...

Gene drive designs for efficient and localisable population suppression using Y-linked editors

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R. Geci, K. Willis and A. Burt,  bioRxiv,  2022.06.29.498122. 2022.
The sterile insect technique (SIT) has been successful in controlling some pest species but is not practicable for many others due to the large numbers of individuals that need to be reared and released. Previous computer modelling has demonstrated that the release of males ...

The suppressive potential of a gene drive in populations of invasive social wasps is currently limited

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A. B. Meiborg, N. R. Faber, B. A. Taylor, B. A. Harpur and G. Gorjanc,  bioRxiv,  2022.06.27.497711. 2022.
Social insects are very successful invasive species, and the continued increase of global trade and transportation has exacerbated this problem. The yellow-legged hornet, Vespa velutina nigrithorax (henceforth Asian hornet), is drastically expanding its range in Western Europe. ...

DriverSEAT: A spatially-explicit stochastic modelling framework for the evaluation of gene drives in novel target species

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M. Legros and L. G. Barrett,  bioRxiv,  2022.06.13.496025. 2022.
Gene drives represent a potentially ground breaking technology for the control of undesirable species or the introduction of desirable traits in wild population, and there is strong interest in applying these technologies to a wide range of species across many domains including ...

Unbalanced selection: the challenge of maintaining a social polymorphism when a supergene is selfish

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A. G. Tafreshi, S. P. Otto and M. Chapuisat,  Philos Trans R Soc Lond B Biol Sci,  377:20210197. 2022.
Supergenes often have multiple phenotypic effects, including unexpected detrimental ones, because recombination suppression maintains associations among co-adapted alleles but also allows the accumulation of recessive deleterious mutations and selfish genetic elements. Yet, ...

Mitotic exchange in female germline stem cells is the major source of Sex Ratio chromosome recombination in Drosophila pseudoobscura

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S. Koury,  bioRxiv,  2022.06.07.495109. 2022.
Sex Ratio chromosomes in Drosophila pseudoobscura are selfish X chromosome variants associated with three non-overlapping inversions. In the male germline, Sex Ratio chromosomes distort segregation of X and Y chromosomes (99:1), thereby skewing progeny sex ratio. In the female ...

Spatial modelling for population replacement of mosquito vectors at continental scale

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N. J. Beeton, A. Wilkins, A. Ickowicz, K. R. Hayes and G. R. Hosack,  PLOS Computational Biology,  18:e1009526. 2022.
Malaria is one of the deadliest vector-borne diseases in the world. Researchers are developing new genetic and conventional vector control strategies to attempt to limit its burden. Novel control strategies require detailed safety assessment to ensure responsible and successful ...

Modeling the impact of genetically modified male mosquitoes in the spatial population dynamics of Aedes aegypti

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M. R. da Silva, P. H. G. Lugão, F. Prezoto and G. Chapiro,  Scientific Reports,  12:9112. 2022.
The mosquito Aedes aegypti is the primary vector of diseases such as dengue, Zika, chikungunya, and yellow fever. Improving control techniques requires a better understanding of the mosquito’s life cycle, including spatial population dynamics in endemic regions. One of the most ...

Combined Trojan Y Chromosome Strategy and Sterile Insect Technique to Eliminate Mosquitoes: Modelling and Analysis

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J. Lyu, M. Gu, S. Wang and K. Cheng,  Mathematical Problems in Engineering,  2022:2373350. 2022.
Sterile insect technique has been successfully applied in the control of agricultural pests; however, it has a limited ability to control mosquitoes. A promising alternative approach is the Trojan Y Chromosome strategy, which works by manipulating the sex ratio of a population ...

Recommendations for environmental risk assessment of gene drive applications for malaria vector control

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J. B. Connolly, J. D. Mumford, D. C. M. Glandorf, S. Hartley, O. T. Lewis, S. W. Evans, G. Turner, C. Beech, N. Sykes, M. B. Coulibaly, J. Romeis, J. L. Teem, W. Tonui, B. Lovett, A. Mankad, A. Mnzava, S. Fuchs, T. D. Hackett, W. G. Landis, J. M. Marshall,  Malar J,  21:152. 2022.
Building on an exercise that identified potential harms from simulated investigational releases of a population suppression gene drive for malaria vector control, a series of online workshops identified nine recommendations to advance future environmental risk assessment of gene ...

Perplexing dynamics of Wolbachia proteins for cytoplasmic incompatibility

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T. Harumoto and T. Fukatsu,  PLOS Biology,  20:e3001644. 2022.
The mechanism of symbiont-induced cytoplasmic incompatibility has been a long-lasting mystery. This Primer explores a new study on Wolbachia’s Cif proteins in PLOS Biology that provides supportive evidence for the “Host-Modification Model,” although the alternative ...

The effect of mating complexity on gene drive dynamics

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P. Verma, R. G. Reeves, S. Simon, M. Otto and C. S. Gokhale,  bioRxiv,  2021.09.16.460618. 2022.
Gene drive technology promises to deliver on some of the global challenges humanity faces today in healthcare, agriculture and conservation. However, there is a limited understanding of the consequences of releasing self-perpetuating transgenic organisms into the wild populations ...

Adversarial interspecies relationships facilitate population suppression by gene drive in spatially explicit models

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Y. Liu, W. Teo, H. Yang and J. Champer,  bioRxiv,  2022.05.08.491087. 2022.
Suppression gene drives are designed to bias their inheritance and increase in frequency in a population, disrupting an essential gene in the process. When the frequency is high enough, the population will be unable to reproduce above the replacement level and could be ...

A metapopulation approach to identify targets for Wolbachia-based dengue control

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A. Reyna-Lara, D. Soriano-Paños, J. H. Arias-Castro, H. J. Martínez and J. Gómez-Gardeñes,  Chaos,  32:041105. 2022.
Over the last decade, the release of Wolbachia-infected Aedes aegypti into the natural habitat of this mosquito species has become the most sustainable and long-lasting technique to prevent and control vector-borne diseases, such as dengue, zika, or chikungunya. However, the ...

The sterile insect technique is protected from evolution of mate discrimination

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J. J. Bull and R. Gomulkiewicz,  PeerJ,  10:e13301. 2022.
Background The sterile insect technique (SIT) has been used to suppress and even extinguish pest insect populations. The method involves releasing artificially reared insects (usually males) that, when mating with wild individuals, sterilize the broods. If administered on a large ...

Propagation of seminal toxins through binary expression gene drives could suppress populations

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J. Hurtado, S. Revale and L. M. Matzkin,  Scientific Reports,  12:6332. 2022.
Gene drives can be highly effective in controlling a target population by disrupting a female fertility gene. To spread across a population, these drives require that disrupted alleles be largely recessive so as not to impose too high of a fitness penalty. We argue that this ...

Modelling homing suppression gene drive in haplodiploid organisms

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Y. Liu and J. Champer,  Proceedings of the Royal Society B: Biological Sciences,  289:20220320. 2022.
Gene drives have shown great promise for suppression of pest populations.These engineered alleles can function by a variety of mechanisms, but themost common is the CRISPR homing drive, which converts wild-type allelesto drive alleles in the germline of heterozygotes. Some ...

Mathematical modelling to assess the feasibility of Wolbachia in malaria vector biocontrol

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S. Andreychuk and L. Yakob,  Journal of Theoretical Biology,  542. 2022.
Releasing mosquitoes transinfected with the endosymbiotic bacterium Wolbachia is a novel strategy for interrupting vector-borne pathogen transmission. Following its success in controlling arboviruses spread by Aedes aegypti, this technology is being adapted for anopheline malaria ...

Finding the strongest gene drive: Simulations reveal unexpected performance differences between Anopheles homing suppression drive candidates

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S. E. Champer, I. K. Kim, A. G. Clark, P. W. Messer and J. Champer,  bioRxiv,  2022.03.28.486009. 2022.
Recent experiments have produced several Anopheles gambiae homing gene drives that disrupt female fertility genes, thereby eventually inducing population collapse. Such drives may be highly effective tools to combat malaria. One such homing drive, based on the zpg promoter ...

Spatial modelling for population replacement of mosquito vectors at continental scale

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N. J. Beeton, A. Wilkins, A. Ickowicz, K. R. Hayes and G. R. Hosack,  bioRxiv,  2021.10.06.463299. 2022.
Malaria is one of the deadliest vector-borne diseases in the world. Researchers are developing new genetic and conventional vector control strategies to attempt to limit its burden. Novel control strategies require detailed safety assessment to ensure responsible and successful ...

Modelling homing suppression gene drive in haplodiploid organisms

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Y. Liu and J. Champer,  bioRxiv,  2021.10.12.464047. 2022.
Gene drives have shown great promise for suppression of pest populations. These engineered alleles can function by a variety of mechanisms, but the most common is the CRISPR homing drive, which converts wild-type alleles to drive alleles in the germline of heterozygotes. Some ...

Rescue by gene swamping as a gene drive deployment strategy

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K. D. Harris and G. Greenbaum,  bioRxiv,  2022.03.08.483503. 2022.
Gene drives are genetic constructs that can spread deleterious alleles with potential application to population suppression of harmful species. Given that a gene drive can potentially spill over to other populations or even other species, control measures and fail-safes ...

Selfish migrants: How a meiotic driver is selected to increase dispersal

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J. N. Runge, H. Kokko and A. K. Lindholm,  J Evol Biol,  2022.
Meiotic drivers are selfish genetic elements that manipulate meiosis to increase their transmission to the next generation to the detriment of the rest of the genome. One example is the t haplotype in house mice, which is a naturally occurring meiotic driver with deleterious ...

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

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P. J. Beaghton and A. Burt,  Theoretical Population Biology,  2022.
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 ...

Uniqueness and stability of periodic solutions for an interactive wild and Wolbachia-infected male mosquito model

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R. Yan and Q. Sun,  Journal of Biological Dynamics,  2022.
We investigate a mosquito population suppression model, which includes the release of Wolbachia-infected males causing incomplete cytoplasmic incompatibility (CI). The model consists of two sub-equations by considering the density-dependent birth rate of wild mosquitoes. By ...

A gene drive does not spread easily in populations of the honey bee parasite Varroa destructor

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N. R. Faber, A. B. Meiborg, G. R. McFarlane, G. Gorjanc and B. A. Harpur,  Apidologie,  52:1112-1127. 2022.
Varroa mites (Varroa destructor) are the most significant threat to beekeeping worldwide. They are directly or indirectly responsible for millions of colony losses each year. Beekeepers are somewhat able to control varroa populations through the use of physical and chemical ...

Gene drives for vertebrate pest control: realistic spatial modelling of eradication probabilities and times for island mouse populations

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A. Birand, P. Cassey, J. V. Ross, J. C. Russell, P. Thomas and T. A. A. Prowse,  Molecular Ecology,  2022.
Abstract Invasive alien species continue to threaten global biodiversity. CRISPR-based gene drives, which can theoretically spread through populations despite imparting a fitness cost, could be used to suppress or eradicate pest populations. We develop an individual-based, ...

Effects of Sterile Males and Fertility of Infected Mosquitoes on Mosquito-Borne Disease Dynamics

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X. L. Sun, S. Q. Liu, Y. F. Lv and Y. Z. Pei,  Bulletin of Mathematical Biology,  84:33. 2022.
By studying an infection-age structured model, we consider the effects of releasing sterile males and the fertility of infected mosquitoes on the mosquito-borne diseases transmission including the extinction of mosquitoes, the elimination and persistence of diseases. Firstly, ...

The prince, the mayor, and the U.S. fish that ate Japan

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C. Elliot,  National Geographic,  2022.
When Crown Prince Akihito visited Chicago on October 3, 1960, his sole request was to visit Shedd Aquarium. Then Mayor Richard J. Daley, an avid angler, presented the prince with a gift that he scooped with a net from one of the tanks himself: 18 bluegills, the official Illinois ...

Modeling CRISPR gene drives for suppression of invasive rodents using a supervised machine learning framework

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S. E. Champer, N. Oakes, R. Sharma, P. García-Díaz, J. Champer and P. W. Messer,  PLoS Comput Biol,  17:e1009660. 2021.
Invasive rodent populations pose a threat to biodiversity across the globe. When confronted with these invaders, native species that evolved independently are often defenseless. CRISPR gene drive systems could provide a solution to this problem by spreading transgenes among ...

Cytoplasmic incompatibility in hybrid zones: infection dynamics and resistance evolution

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E. S. Røed and J. Engelstädter,  Journal of Evolutionary Biology,  2021.
Cytoplasmic incompatibility is an endosymbiont-induced mating incompatibility common in arthropods. Unidirectional cytoplasmic incompatibility impairs crosses between infected males and uninfected females, whereas bidirectional cytoplasmic incompatibility occurs when two host ...

Weakly deleterious natural genetic variation amplifies probability of resistance in multiplexed gene drive systems

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B. S. Khatri and A. Burt,  bioRxiv,  2021.12.23.473701. 2021.
Evolution of resistance is a major barrier to successful deployment of gene drive systems to suppress natural populations. Multiplexed guide RNAs that require resistance mutations in all target cut sites is a promising strategy to overcome resistance. Using novel stochastic ...

Modeling impact and cost-effectiveness of driving-Y gene drives for malaria elimination in the Democratic Republic of the Congo

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N. Metchanun, C. Borgemeister, G. Amzati, J. von Braun, M. Nikolov, P. Selvaraj and J. Gerardin,  Evolutionary Applications,  2021.
Malaria elimination will be challenging in countries that currently continue to bear high malaria burden. Sex-ratio distorting gene drives, such as driving-Y, could play a role in an integrated elimination strategy if they can effectively suppress vector populations. Using a ...

Demographic feedbacks can hamper the spatial spread of a gene drive

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L. Girardin and F. Débarre,  Journal of Mathematical Biology,  83:67. 2021.
This paper is concerned with a reaction–diffusion system modeling the fixation and the invasion in a population of a gene drive (an allele biasing inheritance, increasing its own transmission to offspring). In our model, the gene drive has a negative effect on the fitness of ...

Demographic feedbacks can hamper the spatial spread of a gene drive

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F. Debarre and L. Girardin,  bioRxiv,  2021.12.01.470771. 2021.
This paper is concerned with a reactiond diffusion system modeling the fixation and the invasion in a population of a gene drive (an allele biasing inheritance, increasing its own transmission to offspring). In our model, the gene drive has a negative effect on the fitness of ...

Propagation of seminal toxins through binary expression gene drives can suppress polyandrous populations

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J. Hurtado, S. Revale and L. M. Matzkin,  bioRxiv,  2021.11.23.469777. 2021.
Gene drives can be highly effective in controlling a target population by disrupting a female fertility gene. To spread across a population, these drives require that disrupted alleles be largely recessive so as not to impose too high of a fitness penalty. We argue that this ...

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

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P. J. Beaghton and A. Burt,  bioRxiv,  2021.11.11.468225. 2021.
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 ...

Malaria modeling and optimal control using sterile insect technique and insecticide-treated net

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L. Cai, L. Bao, L. Rose, J. Summers and W. Ding,  Applicable Analysis,  2021.
We investigate a malaria transmission model with SEIR (susceptible-exposed-infected-recovered) classes for the human population, SEI (susceptible-exposed-infected) classes for the wild mosquitoes and an additional class for the sterile mosquitoes. The basic reproduction number ...

Population replacement gene drive characteristics for malaria elimination in a range of seasonal transmission settings: a modeling study

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S. Leung, N. Windbichler, E. Wenger, C. Bever and P. Selvaraj,  bioRxiv,  2021.11.01.466856. 2021.
Genetically engineering mosquitoes is a promising new vector control strategy to reinvigorate the fight against malaria in Sub-Saharan Africa. Using an agent-based model of malaria transmission with vector genetics, we examine the impacts of releasing population-replacement gene ...

Modeling the efficacy of CRISPR gene drive for schistosomiasis control

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R. E. Grewelle, J. Perez-Saez, J. Tycko, E. K. O. Namigai, C. G. Rickards and G. A. De Leo,  bioRxiv,  2021.10.29.466423. 2021.
CRISPR gene drives could revolutionize the control of infectious diseases by accelerating the spread of engineered traits that limit parasite transmission in wild populations. While much effort has been spent developing gene drives in mosquitoes, gene drive technology in molluscs ...

A gene drive does not spread easily in populations of the honey bee parasite Varroa destructor

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N. R. Faber, A. B. Meiborg, G. R. McFarlane, G. Gorjanc and B. A. Harpur,  Apidologie,  2021.
Varroa mites (Varroa destructor) are the most significant threat to beekeeping worldwide. They are directly or indirectly responsible for millions of colony losses each year. Beekeepers are somewhat able to control varroa populations through the use of physical and chemical ...

Modeling homing suppression gene drive in haplodiploid organisms

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Y. Liu and J. Champer,  bioRxiv,  2021.10.12.464047. 2021.
Gene drives have shown great promise for suppression of pest populations. These engineered alleles can function by a variety of mechanisms, but the most common is the CRISPR homing drive, which converts wild-type alleles to drive alleles in the germline of heterozygotes. Some ...

Spatial modelling for population replacement of mosquito vectors at continental scale

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N. J. Beeton, A. Wilkins, A. Ickowicz, K. R. Hayes and G. R. Hosack,  bioRxiv,  2021.10.06.463299. 2021.
We explore transmission of the gene drive between the subspecies, different hybridisation mechanisms, the effects of both local dispersal and potential wind-aided migration to the spread, and the development of resistance to the gene drive. We find that given best current ...

Discrete dynamical models on Wolbachia infection frequency in mosquito populations with biased release ratios

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Y. Shi and B. Zheng,  Journal of Biological Dynamics,  2021.
We develop two discrete models to study how supplemental releases affect the Wolbachia spreading dynamics in cage mosquito populations. The first model focuses on the case when only infected males are released at each generation. This release strategy has been proved to be ...

The effect of mating complexity on gene drive dynamics

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P. Verma, R. G. Reeves, S. Simon, M. Otto and C. S. Gokhale,  bioRxiv,  2021.09.16.460618. 2021.
Gene drive technology is being presented as a means to deliver on some of the global challenges humanity faces today in healthcare, agriculture and conservation. However, there is a limited understanding of the consequences of releasing self-perpetuating transgenic organisms into ...

Predicting the spread and persistence of genetically modified dominant sterile male mosquitoes

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A. Ickowicz, S. D. Foster, G. R. Hosack and K. R. Hayes,  Parasites and Vectors,  14:480. 2021.
Reproductive containment provides an opportunity to implement a staged-release strategy for genetic control of malaria vectors, in particular allowing predictions about the spread and persistence of (self-limiting) sterile and male-biased strains to be compared to outcomes before ...

Evolutionary robustness of killer meiotic drives

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P. G. Madgwick and J. B. Wolf,  Evolution Letters,  2021.
A meiotic driver is a selfish genetic element that interferes with the process of meiosis to promote its own transmission. The most common mechanism of interference is gamete killing, where the meiotic driver kills gametes that do not contain it. A killer meiotic driver is ...

Gene drive escape from resistance depends on mechanism and ecology

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F. Cook, J. J. Bull and R. Gomulkiewicz,  bioRxiv,  2021.08.30.458221. 2021.
Gene drives can potentially be used to suppress pest populations, and the advent of CRISPR technology has made it feasible to engineer them in many species, especially insects. What remains largely unknown for implementations is whether anti-drive resistance will evolve to block ...

Sterile males and females can synergistically suppress wild pests targeted by sterile insect technique

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Y. Ikegawa, K. Ito, C. Himuro and A. Honma,  Journal of Theoretical Biology,  530. 2021.
We constructed a mathematical model to examine the contribution of sterile males and females to the pest-control effect and the synergy between them. We consider that males seek out and court females in accord with their own female searching ability and preference, and that ...

A common gene drive language eases regulatory process and eco-evolutionary extensions

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P. Verma, R. G. Reeves and C. S. Gokhale,  BMC Ecology and Evolution,  21:156. 2021.
Synthetic gene drive technologies aim to spread transgenic constructs into wild populations even when they impose organismal fitness disadvantages. The extraordinary diversity of plausible drive mechanisms and the range of selective parameters they may encounter makes it very ...

Risk management recommendations for environmental releases of gene drive modified insects

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Y. Devos, J. D. Mumford, M. B. Bonsall, D. C. M. Glandorf and H. D. Quemada,  Biotechnology Advances,  2021.
The ability to engineer gene drives (genetic elements that bias their own inheritance) has sparked enthusiasm and concerns. Engineered gene drives could potentially be used to address long-standing challenges in the control of insect disease vectors, agricultural pests and ...

Autocatalytic-protection for an unknown locus CRISPR-Cas countermeasure for undesired mutagenic chain reactions

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E. Schonfeld, E. Schonfeld and D. Schonfeld,  Journal of Theoretical Biology,  528:110831. 2021.
The mutagenic chain reaction (MCR) is a genetic tool to use a CRISPR–Cas construct to introduce a homing endonuclease, allowing gene drive to influence whole populations in a minimal number of generations (Esvelt et al., 2014, Gantz and Bier, 2015, Gantz and Bier, 2016). The ...

Part of ‘master plan’: Researchers receive grant to fund research on malaria

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L. Huang,  The Daily Californian,  2021.
Early this month, The Marshall Lab at UC Berkeley received an $800,000 grant from the Bill and Melinda Gates Foundation to fund its research on genetics-based malaria mosquito control. The Marshall Lab is one of many teams playing a part in the Gates Foundation’s decades-long ...

Marshall Lab receives Gates grant for genetics-based malaria mosquito control

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Berkeley Public Health,  Berkeley Public Health,  2021.
Berkeley Public Health Associate Professor John Marshall, PhD, and Assistant Project Scientist Héctor Sánchez, PhD, have received an $800,000 grant from the Bill & Melinda Gates Foundation to support their lab’s work in genetics-based malaria mosquito control. Malaria, the ...

Fine-scale estimation of key life-history parameters of malaria vectors: implications for next-generation vector control technologies

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A. L. Morris, A. Ghani and N. Ferguson,  Parasites and Vectors,  14:311. 2021.
Mosquito control has the potential to significantly reduce malaria burden on a region, but to influence public health policy must also show cost-effectiveness. Gaps in our knowledge of mosquito population dynamics mean that mathematical modelling of vector control interventions ...

MGDrivE 2: A simulation framework for gene drive systems incorporating seasonality and epidemiological dynamics

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S. L. Wu, J. B. Bennett, C. H. Sánchez, A. J. Dolgert, T. M. León and J. M. Marshall,  PLoS Comput Biol,  17:e1009030. 2021.
We present MGDrivE 2 (Mosquito Gene Drive Explorer 2): a significant development from the MGDrivE 1 simulation framework that investigates the population dynamics of a variety of gene drive architectures and their spread through spatially-explicit mosquito populations. Key ...

A gene drive does not spread easily in populations of the honey bee parasite Varroa destructor

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N. R. Faber, A. B. Meiborg, G. R. McFarlane, G. Gorjanc and B. A. Harpur,  bioRxiv,  2021.04.30.442149. 2021.
Varroa mites (Varroa destructor) are the most significant threat to beekeeping worldwide. They are directly or indirectly responsible for millions of colony losses each year. Beekeepers are somewhat able to control Varroa populations through the use of physical and chemical ...

Invasion and maintenance of meiotic drivers in populations of ascomycete fungi

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I. Martinossi-Allibert, C. Veller, S. L. Ament-Velasquez, A. A. Vogan, C. Rueffler and H. Johannesson,  Evolution,  20. 2021.
Meiotic drivers (MDs) are selfish genetic elements that are able to become overrepresented among the products of meiosis. This transmission advantage makes it possible for them to spread in a population even when they impose fitness costs on their host organisms. Whether an MD ...

Double drives and private alleles for localised population genetic control

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K. Willis and A. Burt,  PLOS Genetics,  17. 2021.
ynthetic gene drive systems that are able to spread though populations because they are inherited at a greater-than-Mendelian rate have the potential to form the basis for new, highly efficient pest control measures. The most efficient such strategies use natural gene flow to ...

Quantifying the risk of vector-borne disease transmission attributable to genetically modified vectors

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G. R. Hosack, A. Ickowicz and K. R. Hayes,  Royal Society Open Science,  8:201525. 2021.
The relative risk of disease transmission caused by the potential release of transgenic vectors, such as through sterile insect technique or gene drive systems, is assessed with comparison with wild-type vectors. The probabilistic risk framework is demonstrated with an assessment ...

A confinable home and rescue gene drive for population modification

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N. P. Kandul, J. Liu, J. B. Bennett, J. M. Marshall and O. S. Akbari,  eLife,  10:e65939. 2021.
Homing based gene drives, engineered using CRISPR/Cas9, have been proposed to spread desirable genes throughout populations. However, invasion of such drives can be hindered by the accumulation of resistant alleles. To limit this obstacle, we engineer a confinable population ...

Designing gene drives to limit spillover to non-target populations

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G. Greenbaum, M. W. Feldman, N. A. Rosenberg and J. Kim,  PLOS Genetics,  17:e1009278. 2021.
We develop mathematical models of gene-drive dynamics that incorporate migration between a target and non-target populations to investigate the possibility of effectively applying a gene drive in the target population while limiting its spillovers to the non-target population ...

Ecological Modeling in Risk Assessment of Gene Drives

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Hector Quemada and David O'Brochta,  2021.
Unlike non-gene drive organisms, which can be limited in time and space and therefore provide data in small scale tests that can be relevant to large scale releases, the potential for large-scale spread from a limited release, even in well-isolated trials, means that reliance on ...

GeneConvene Webinar Series on: Ecological Modeling in Risk Assessment of Gene Drives

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Hector Quemada and David O'Brochta,  2021.
Unlike non-gene drive organisms, which can be limited in time and space and therefore provide data in small scale tests that can be relevant to large scale releases, the potential for large-scale spread from a limited release, even in well-isolated trials, means that reliance on ...

Demographic feedbacks can hamper the spatial spread of a gene drive

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L. Girardin and F. Débarre,  arXiv,  2021.
Our results indicate that taking into account the interplay between population dynamics and population genetics might actually be crucial, as it can effectively reverse the direction of the invasion and lead to failure. Our findings can be extended to other bistable systems, such ...

Double drives and private alleles for localised population genetic control

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K. Willis and A. Burt,  bioRxiv,  2021.01.08.425856. 2021.
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 ...

Self-Deleting Genes Project To Tackle Mosquito-Borne Diseases

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D. Ozdemir,  INTERESTING ENGINEERING,  2021.
Did you know that mosquitoes kill at least 725,000 persons every year? They truly are one of the world's deadliest animals which is the reason why scientists from all around are trying to find new ways of dealing with them. Controlling mosquito populations and preventing them ...

Suppression gene drive in continuous space can result in unstable persistence of both drive and wild-type alleles

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J. Champer, I. K. Kim, S. E. Champer, A. G. Clark and P. W. Messer,  Mol Ecol,  2021.
Using spatially explicit simulations, we show that the release of a suppression drive can result in what we term "chasing" dynamics, in which wild-type individuals recolonize areas where the drive locally eliminated the population. Despite the drive subsequently reconquering ...

Self-deleting genes promise risk-free genetic engineering of mosquitoes

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D. Quick,  New Atlas,  2020.
A new project by Texas A&M AgriLife Research is looking to enable "test runs" of genetic changes to mosquitoes that are automatically deleted. Various angles of attack using genetic engineering to combat mosquitoes have been pursued in recent years, including modifying them so ...

Self-deleting genes to be tested as part of mosquito population control concept

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B. Hays,  UPI,  2020.
Scientists at Texas A&M have developed a new technique for altering the genes of mosquitoes -- the new technology will cause genetic changes to self-delete from the mosquitoes' genome. Thanks to the breakthrough, described Monday in the Philosophical Transactions of the Royal ...

$3.9M project on self-deleting genes takes aim at mosquito-borne diseases

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O. Kuchment,  AGRILIFE Today,  2020.
To control mosquito populations and prevent them from transmitting diseases such as malaria, many researchers are pursuing strategies in mosquito genetic engineering. A new Texas A&M AgriLife Research project aims to enable temporary “test runs” of proposed genetic changes in ...

Self-deleting genes tested as part of the concept of mosquito population control

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charlottelarson,  NEWYORK NEWS TIMES,  2020.
Most genetic engineering strategies designed to control mosquito populations, and their ability to spread diseases such as malaria, require gene editing to be combined with gene drives. Gene drives allow altered DNA to spread rapidly throughout the population.

Making gene drive biodegradable

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J. Zapletal, N. Najmitabrizi, M. Erraguntla, M. A. Lawley, K. M. Myles and Z. N. Adelman,  Philosophical Transactions of the Royal Society B: Biological Sciences,  376:20190804. 2020.
Here, we consider the inclusion of self-elimination mechanisms into the design of homing-based gene drive transgenes. This approach not only caused the excision of the gene drive transgene, but also generates a transgene-free allele resistant to further action by the gene drive. ...

Evading resistance to gene drives

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R. Gomulkiewicz, M. L. Thies and J. J. Bull,  bioRxiv,  2020.08.27.270611. 2020.
Our analyses suggest that among gene drives that cause moderate suppression, toxin-antidote systems are less apt to select for resistance than homing drives. Single drives of moderate effect might cause only moderate population suppression, but multiple drives (perhaps delivered ...

Modelling the Wolbachia incompatible insect technique: strategies for effective mosquito population elimination

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D. E. Pagendam, B. J. Trewin, N. Snoad, S. A. Ritchie, A. A. Hoffmann, K. M. Staunton, C. Paton and N. Beebe,  BMC Biology,  18:13. 2020.
We introduce a simple Markov population process model for studying mosquito populations subjected to a Wolbachia-IIT programme which exhibit an unstable equilibrium threshold. The model is used to study, in silico, scenarios that are likely to yield a successful elimination ...

Design and analysis of CRISPR-based underdominance toxin-antidote gene drives

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J. Champer, S. E. Champer, I. K. Kim, A. G. Clark and P. W. Messer,  Evolutionary Applications,  18. 2020.
We model drives which target essential genes that are either haplosufficient or haplolethal, using nuclease promoters with expression restricted to the germline, promoters that additionally result in cleavage activity in the early embryo from maternal deposition, and promoters ...

Split drive killer-rescue provides a novel threshold-dependent gene drive

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M. P. Edgington, T. Harvey-Samuel and L. Alphey,  Scientific Reports,  10. 2020.
Population genetics mathematical models are developed here to demonstrate the threshold-dependent nature of the proposed system and its robustness to imperfect homing, incomplete penetrance of toxins and transgene fitness costs, each of which are of practical significance given ...

Split drive killer-rescue provides a novel threshold-dependent gene drive

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M. P. Edgington, T. Harvey-Samuel and L. Alphey,  Scientific Reports,  10:13. 2020.
We show that although end-joining repair mechanisms may cause the system to break down, under certain conditions, it should persist over time scales relevant for genetic control programs. The potential of such a system to provide localised population suppression via sex ratio ...

Further guidance required for assessment of gene drive technology, says EFSA

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N. Foote,  Euractiv,  2020.
After being mandated by the European Commission, EFSA’s experts on genetically modified organisms (GMOs) published the scientific opinion related to engineered gene drives on Thursday (12 November), specifically focusing on gene drive modified disease-transmitting insects, ...

Adequacy and sufficiency evaluation of existing EFSA guidelines for the molecular characterisation, environmental risk assessment and post-market environmental monitoring of genetically modified insects containing engineered gene drives

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E. Panel o. G. M. Organisms, H. Naegeli, J.-L. Bresson, T. Dalmay, I. C. Dewhurst, M. M. Epstein, P. Guerche, J. Hejatko, F. J. Moreno, E. Mullins, F. Nogué, N. Rostoks, J. J. Sánchez Serrano, G. Savoini, E. Veromann, F. Veronesi, M. B. Bonsall, J. Mumfor,  EFSA Journal,  18:e06297. 2020.
As a proactive measure, the European Food Safety Authority (EFSA) has been requested by the European Commission to review whether its previously published guidelines for the risk assessment of genetically modified animals (EFSA, 2012 and 2013), including insects (GMIs), are ...

EFSA advises on risk assessment of engineered gene drives

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EFSA,  European Food and Safety Authority,  2020.
EFSA’s existing guidelines for the risk assessment of genetically modified animals are adequate for evaluating risks associated with gene drive modified insects. However, further guidance is needed for some areas, such as molecular characterisation, environmental risk ...

Modeling CRISPR gene drives for suppression of invasive rodents

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S. E. Champer, N. Oakes, R. Sharma, P. García-Díaz, J. Champer and P. W. Messer,  bioRxiv,  2020.11.05.369942. 2020.
Here, we develop a high-fidelity model of an island population of invasive rodents that includes three types of suppression gene drive systems. The individual-based model is spatially explicit and allows for overlapping generations and a fluctuating population size. Our model ...

Gene Drives across engineered fitness valleys: Modeling a design to prevent drive spillover.

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F. J. H. de Haas and S. Otto,  bioRxiv,  2020.10.29.360404. 2020.
We model a proposed drive system that transitions in time from a low threshold drive system (homing-based gene drive) to a high threshold drive system (underdominance) using daisy chain technology. This combination leads to a spatially restricted drive strategy while maintaining ...

MGDrivE 2: A simulation framework for gene drive systems incorporating seasonality and epidemiological dynamics

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S. L. Wu, J. B. Bennett, H. M. Sanchez C, A. J. Dolgert, T. M. Leon and J. M. Marshall,  bioRxiv,  2020.10.16.343376. 2020.
We present MGDrivE 2 (Mosquito Gene Drive Explorer 2): an extension of and development from the MGDrivE 1 simulation framework that investigates the population dynamics of a variety of gene drive architectures and their spread through spatially-explicit mosquito populations.

Dynamics of Wild and Sterile Mosquito Population Models with Delayed Releasing

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L. M. Cai,  International Journal of Bifurcation and Chaos,  30:15. 2020.
We extend the previous ODE models to the delayed releasing models in two different ways of releasing sterile mosquitos, where both constant and exponentially distributed delays are considered, respectively. By applying the theory and methods of delay differential equations, the ...

Suppressing evolution in genetically engineered systems through repeated supplementation

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N. C. Layman, B. M. Tuschhoff, A. J. Basinski, C. H. Remien, J. J. Bull and S. L. Nuismer,  Evolutionary Applications,  12. 2020.
Genetically engineered organisms are prone to evolve in response to the engineering. This evolution is often undesirable and can negatively affect the purpose of the engineering. Methods that maintain the stability of engineered genomes are therefore critical to the successful ...

Vector genetics, insecticide resistance and gene drives: An agent-based modeling approach to evaluate malaria transmission and elimination

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P. Selvaraj, E. A. Wenger, D. Bridenbecker, N. Windbichler, J. R. Russell, J. Gerardin, C. A. Bever and M. Nikolov,  PloS Computational Biology,  16:21. 2020.
Here, we investigate the reduced efficacy of current vector control measures in the presence of insecticide resistance and evaluate the likelihood of achieving local malaria elimination using gene drive mosquitoes released into a high transmission setting alongside other vector ...

Modelling the suppression of a malaria vector using a CRISPR-Cas9 gene drive to reduce female fertility

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A. R. North, A. Burt and H. C. J. Godfray,  BMC Biology,  18:98. 2020.
Gene drives based on CRISPR-Cas9 technology are increasingly being considered as tools for reducing the capacity of mosquito populations to transmit malaria, and one of the most promising options is driving endonuclease genes that reduce the fertility of female mosquitoes. Here, ...

Incorporating Characteristics of Gene Drive Engineered Ae. aegypti as Methods to Reduce Dengue and Zika Virus into the Bayesian Network – Relative Risk Model, Using Ponce, Puerto Rico as a Case Study

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S. R. Eikenbary,  WWU Graduate School Collection,  2020.
The Bayesian network relative risk model can perform the risk assessment of gene drive engineered Ae. aegypti for vector control and as part of an adaptive management strategy to reduce dengue and Zika transmission. This study illustrates how the BN-RRM can integrate gene drive ...

Modeling the suppression dynamics of Aedes mosquitoes with mating inhomogeneity

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M. Huang and L. Hu,  Journal of Biological Dynamics,  14:656-678. 2020.
In this work, we introduce a delay differential equation model with mating inhomogeneity to discuss mosquito population suppression based on Wolbachia. Our analyses show that the wild mosquitoes could be eliminated if either the adult mortality rate exceeds the threshold δ∗A ...

A One-Sided Competition Mathematical Model for the Sterile Insect Technique

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A. Ben Dhahbi, Y. Chargui, S. M. Boulaaras and S. Ben Khalifa,  Complexity,  2020:12. 2020.
We study a simple mathematical model describing the dynamics of a wild-type pest insects population experiencing competition from sterile insects (one-sided competition).

On Nonlinear Pest/Vector Control via the Sterile Insect Technique: Impact of Residual Fertility

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M. S. Aronna and Y. Dumont,  Bulletin of Mathematical Biology,  82:29. 2020.
We consider a minimalist model for the Sterile Insect Technique (SIT), assuming that residual fertility can occur in the sterile male population.

Invasion and maintenance of spore killers in populations of ascomycete fungi

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I. Martinossi-Allibert, C. Veller, S. L. Ament-Velásquez, A. A. Vogan, C. Rueffler and H. Johannesson,  bioRxiv,  2020.04.06.026989. 2020.
We show how ploidy level, rate of selfing, and efficiency of spore killing affect the invasion probability of a driving allele and the conditions for its stable coexistence with the non-driving allele. Our model can be adapted to different fungal life-cycles, and is applied here ...

Field performance of sterile male mosquitoes released from an uncrewed aerial vehicle

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J. Bouyer, N. J. Culbert, A. H. Dicko, M. G. Pacheco, J. Virginio, M. C. Pedrosa, L. Garziera, A. T. M. Pinto, A. Klaptocz, J. Germann, T. Wallner, G. Salvador-Herranz, R. A. Herrero, H. Yamada, F. Balestrino and M. J. B. Vreysen,  Science Robotics,  5:10. 2020.
Genetic control methods of mosquito vectors of malaria, dengue, yellow fever, and Zika are becoming increasingly popular due to the limitations of other techniques such as the use of insecticides. The sterile insect technique is an effective genetic control method to manage ...

Simulation models from: Can CRISPER-mediated gene drive work in pest and beneficial haplodiploid species?

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J. Li and B. Tabashnik,  Dryad,  2020.
Gene drives based on CRISPR/Cas9 have the potential to reduce the enormous harm inflicted by crop pests and insect vectors of human disease, as well as to bolster valued species. In contrast with extensive empirical and theoretical studies in diploid organisms, little is known ...

Simulating effects of fitness and dispersal on the use of Trojan sex chromosomes for the management of invasive species

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C. C. Day, E. L. Landguth, R. K. Simmons, W. P. Baker, A. R. Whiteley, P. M. Lukacs and A. Bearlin,  Journal of Applied Ecology,  2020.
The use of Trojan Y chromosomes (TYC) for controlling invasive species involves manipulating the sex chromosomes of captive-raised individuals. Following release, the offspring of these individuals consist of only one sex, thereby skewing the sex ratio of the invasive population ...

Optimal control and analysis of a modified trojan Y-Chromosome strategy

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M. A. Beauregard, R. D. Parshad, S. Boon, H. Conaway, T. Griffin and J. J. Lyu,  Ecological Modelling,  416. 2020.
The Trojan Y Chromosome (TYC) strategy is a promising eradication method that attempts to manipulate the female to male ratio to promote the reduction of the population of an invasive species. The manipulation stems from an introduction of sex-reversed males, called supermales, ...

Gene Drives: Dynamics and Regulatory Matters-A Report from the Workshop “Evaluation of Spatial and Temporal Control of Gene Drives,” April 4-5, 2019, Vienna

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B. Giese, J. L. Friess, N. H. Barton, P. W. Messer, F. Debarre, M. F. Schetelig, N. Windbichler, H. Meimberg and C. Boete,  Bioessays,  41:3. 2019.
Gene Drives are regarded as future tools with a high potential for population control. Due to their inherent ability to overcome the rules of Mendelian inheritance, gene drives (GD) may spread genes rapidly through populations of sexually reproducing organisms. A release of ...

Ecological effects on underdominance threshold drives for vector control

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D. Khamis, C. El Mouden, K. Kura and M. B. Bonsall,  Journal of Theoretical Biology,  456:1-15. 2018.
Here, ecological and epidemiological dynamics are coupled to a model of mosquito genetics to investigate theoretically the impact of different types of underdominance gene drive on disease prevalence. We model systems with two engineered alleles carried either on the same pair ...

Population Consequences of Releasing Sex-Reversed Fish: Applications and Concerns

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C. Wederkind,  Sex Control in Aquaculture,  Chp 8:179-188. 2018.
Sex differentiation is generally more labile in gonochoristic fish than it is, for example, in birds and mammals. Environmentally induced sex reversal is, therefore, often possible, and creates genotype‐phenotype mismatches that can be useful in population management. ...

A spatially discrete, integral projection model and its application to invasive carp

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R. A. Erickson, E. A. Eager, P. M. Kocovsky, D. C. Glover, J. L. Kallis and K. R. Long,  Ecological Modelling,  387:163-171. 2018.
Natural resource managers and ecologists often desire an understanding of spatial dynamics such as migration, dispersion, and meta-population dynamics. Network-node models can capture these salient features. Additionally, the state-variable used with many species may be ...

Pest demography critically determines the viability of synthetic gene drives for population control

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K. E. Wilkins, T. A. A. Prowse, P. Cassey, P. Q. Thomas and J. V. Ross,  Mathematical Biosciences,  305:160-169. 2018.
Synthetic gene drives offer a novel solution for the control of invasive alien species. CRISPR-based gene drives can positively bias their own inheritance, and comprise a DNA sequence that is replicated by homologous recombination. Since gene drives can be positioned to silence ...

Genetics-based methods for agricultural insect pest management

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N. Alphey and M. B. Bonsall,  Agricultural and Forest Entomology,  20:131-140. 2018.
Abstract The sterile insect technique is an area-wide pest control method that reduces agricultural pest populations by releasing mass-reared sterile insects, which then compete for mates with wild insects. Contemporary genetics-based technologies use insects that are homozygous ...

The optimal implementation of the Trojan Y chromosome eradication strategy of invasive species

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M. R. Kelly and X. Y. Wang,  Journal of Biological Systems,  25:399-418. 2017.
Invasive aquatic species continue to be a persistent problem around the world. The Trojan Y Chromosome (TYC) eradication strategy has recently been developed to help fight the problem in aquatic systems by targeting only the invasive species, sparing native marine stock. It ...

Daisyfield gene drive systems harness repeated genomic elements as a generational clock to limit spread

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J. Min, C. Noble, D. Najjar and K. M. Esvelt,  bioRxiv,  104877. 2017.
Here we describe a novel form of gene drive based on the introduction of multiple copies of an engineered ‘daisy’ sequence into repeated elements of the genome. Each introduced copy encodes guide RNAs that target one or more engineered loci carrying the CRISPR nuclease gene ...

Lethal Gene Drive Selects Inbreeding

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J. J. Bull,  bioRxiv,  046847. 2016.
ere, population genetic models are used to consider the evolution of inbreeding (specifically selfing) as a possible response to a recessively lethal HEG with complete segregation distortion. Numerical analyses indicate a rich set of outcomes, but selfing often evolves in ...

Stochastic models for the Trojan Y-Chromosome eradication strategy of an invasive species

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X. Y. Wang, J. R. Walton and R. D. Parshad,  Journal of Biological Dynamics,  10:179-199. 2015.
The Trojan Y-Chromosome (TYC) strategy, an autocidal genetic bio-control method, has been proposed to eliminate invasive alien species. In this work, we develop a Markov jump process model for this strategy, and we verify that there is a positive probability for wild-type females ...

Global existence and asymptotic behavior of a model for biological control of invasive species via supermale introduction

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R. D. Parshad, S. Kouachi and J. B. Gutierrez,  Communications in Mathematical Sciences,  11:971-992. 2013.
The purpose of this manuscript is to propose a model for the biological control of invasive species, via introduction of phenotypically modified organisms into a target population. We are inspired by the earlier Trojan Y Chromosome model [J.B. Gutierrez, J.L. Teem, J. Theo. Bio., ...

Demographic effects on the use of genetic options for the control of mosquitofish, Gambusia holbrooki

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R. E. Thresher, M. Canning and N. J. Bax,  Ecological Applications,  23:801-814. 2013.
This study tests the sensitivity of genetically based pest control options based on sex ratio distortion to intra-and intersexual aggressive interactions that affect male and female survival and fitness. Data on these interactions and their impacts were gathered for the ...

Analysis of the Trojan Y-Chromosome eradication strategy for an invasive species

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X. Y. Wang, J. R. Walton, R. D. Parshad, K. Storey and M. Boggess,  Journal of Mathematical Biology,  68:1731-1756. 2013.
The Trojan Y-Chromosome (TYC) strategy, an autocidal genetic biocontrol method, has been proposed to eliminate invasive alien species. In this work, we analyze the dynamical system model of the TYC strategy, with the aim of studying the viability of the TYC eradication and ...

Existence of global attractor for the Trojan Y Chromosome model

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X. P. Zhao, B. Liu and N. Duan,  Electronic Journal of Qualitative Theory of Differential Equations,  2011.
This paper is concerned with the long time behavior of solution for the equation derived by the Trojan Y Chromosome (TYC) model with spatial spread. Based on the regularity estimates for the semigroups and the classical existence theorem of global attractors, we prove that this ...

Analysis of the Trojan Y chromosome model for eradication of invasive species in a dendritic riverine system

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J. B. Gutierrez, M. K. Hurdal, R. D. Parshad and J. L. Teem,  Journal of Mathematical Biology,  64:319-340. 2011.
The use of Trojan Y chromosomes has been proposed as a genetic strategy for the eradication of invasive species. The strategy is particularly relevant to invasive fish species that have XY sex determination system and are amenable to sex-reversal. In this paper we study the ...

The Impact of Dissociation on Transposon-Mediated Disease Control Strategies

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J. M. Marshall,  Genetics,  178:1673-1682. 2008.
Vector-borne diseases such as malaria and dengue fever continue to be a major health concern through much of the world. The emergence of chloroquine-resistant strains of malaria and insecticide-resistant mosquitoes emphasize the need for novel methods of disease control. ...

Can transposable elements be used to drive disease refractoriness genes into vector populations?

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M. G. Kidwell and J. M. C. Ribeiro,  Parasitology Today,  8:325-329. 1992.
A number of biological procedures are currently being considered as alternatives to insecticide-based methods for the control of insect vectors of disease. Among these are the adaptation of various genetic mechanisms to drive genes of interest, such as refractoriness to malaria ...