This is a database of peer-reviewed literature that focuses on Genetic Biocontrol research. The latest are shown here.
A CRISPR endonuclease gene drive reveals distinct mechanisms of inheritance bias
Background
CRISPR/Cas gene drives can bias transgene inheritance through different mechanisms. Homing drives are designed to replace a wild-type allele with a copy of a drive element on the homologous chromosome. In Aedes aegypti, the sex-determining locus is closely linked to the white gene, which was previously used as a target for a homing drive element (wGDe). Here, through an analysis using this linkage we show that in males inheritance bias of wGDe did not occur by homing, rather through increased propagation of the donor drive element.
Verkuijl, S. A., Gonzalez, E., Li, M., Ang, J. X., Kandul, N. P., Anderson, M. A., … & Alphey, L. (2022). A CRISPR endonuclease gene drive reveals distinct mechanisms of inheritance bias. Nature Communications, 13(1), 7145.
Why Wolbachia-induced cytoplasmic incompatibility is so common
Background
Wolbachia are obligately intracellular alphaproteobacteria that infect approximately half of all insect species. Maternal inheritance of these endosymbionts produces selection to enhance female fitness. In addition to mutualistic phenotypes such as nutrient provisioning, Wolbachia produce various reproductive manipulations that favor infected females. Most common is cytoplasmic incompatibility, namely reduced embryo viability when Wolbachia-infected males fertilize Wolbachia-uninfected females. The regular loss of cytoplasmic incompatibility indicates this phenotype is not favored by natural selection among Wolbachia variants within host populations.
Turelli, M., Katznelson, A., & Ginsberg, P. S. (2022). Why Wolbachia-induced cytoplasmic incompatibility is so common. Proceedings of the National Academy of Sciences, 119(47), e2211637119.
Driving down malaria transmission with engineered gene drives
Background
The last century has witnessed the introduction, establishment and expansion of mosquito-borne diseases into diverse new geographic ranges. Malaria is transmitted by female Anopheles mosquitoes. Despite making great strides over the past few decades in reducing the burden of malaria, transmission is now on the rise again, in part owing to the emergence of mosquito resistance to insecticides, antimalarial drug resistance and, more recently, the challenges of the COVID-19 pandemic, which resulted in the reduced implementation efficiency of various control programs. The utility of genetically engineered gene drive mosquitoes as tools to decrease the burden of malaria by controlling the disease-transmitting mosquitoes is being evaluated.
Garrood, W. T., Cuber, P., Willis, K., Bernardini, F., Page, N. M., & Haghighat-Khah, R. E. (2022). Driving down malaria transmission with engineered gene drives. Frontiers in Genetics, 13.
Leveraging a natural murine meiotic drive to suppress invasive populations
Background
Invasive rodents pose a significant threat to global biodiversity, contributing to countless extinctions, particularly on islands. Genetic biocontrol has considerable potential to control invasive populations but has not been developed in mice. Here, we develop a suppression gene drive strategy for mice that leverages a modified naturally occurring element with biased transmission to spread faulty copies of a haplosufficient female fertility gene (tCRISPR). In silico modeling of island populations using a range of realistic parameters predicts robust eradication. We also demonstrate proof of concept for this strategy in laboratory mice. This work marks a significant step toward the development of a gene drive for the suppression of invasive mice.
Gierus, L., Birand, A., Bunting, M. D., Godahewa, G. I., Piltz, S. G., Oh, K. P., … & Thomas, P. Q. (2022). Leveraging a natural murine meiotic drive to suppress invasive populations. Proceedings of the National Academy of Sciences, 119(46), e2213308119.
A sterile insect technique pilot trial on Captiva Island: defining mosquito population parameters for sterile male releases using mark–release–recapture
Background
The sterile insect technique (SIT), which involves area-wide inundative releases of sterile insects to suppress the reproduction of a target species, has proven to be an effective pest control method. The technique demands the continuous release of sterilized insects in quantities that ensure a high sterile male:wild male ratio for the suppression of the wild population over succeeding generations.
Carvalho, D. O., Morreale, R., Stenhouse, S., Hahn, D. A., Gomez, M., Lloyd, A., & Hoel, D. (2022). A sterile insect technique pilot trial on Captiva Island: defining mosquito population parameters for sterile male releases using mark–release–recapture. Parasites & Vectors, 15(1), 1-14.
Assessing single-locus CRISPR/Cas9-based gene drive variants in the mosquito Aedes aegypti via single-generation crosses and modeling
Background
The yellow fever mosquito Aedes aegypti is a major vector of arthropod-borne viruses, including dengue, chikungunya, and Zika viruses. A novel approach to mitigate arboviral infections is to generate mosquitoes refractory to infection by overexpressing antiviral effector molecules. Such an approach requires a mechanism to spread these antiviral effectors through a population, for example, by using CRISPR/Cas9-based gene drive systems.
Reid, W., Williams, A. E., Sanchez-Vargas, I., Lin, J., Juncu, R., Olson, K. E., & Franz, A. W. (2022). Assessing single-locus CRISPR/Cas9-based gene drive variants in the mosquito Aedes aegypti via single-generation crosses and modeling. G3, 12(12), jkac280.
CRISPR Cas9 mediated knockout of sex determination pathway genes in Aedes aegypti
Background
The vector role of Aedes aegypti for viral diseases including dengue and dengue hemorrhagic fever makes it imperative for its proper control. Despite various adopted control strategies, genetic control measures have been recently focused against this vector. CRISPR Cas9 system is a recent and most efficient gene editing tool to target the sex determination pathway genes in Ae. aegypti.
Zulhussnain, M., Zahoor, M. K., Ranian, K., Ahmad, A., & Jabeen, F. (2023). CRISPR Cas9 mediated knockout of sex determination pathway genes in Aedes aegypti. Bulletin of Entomological Research, 113(2), 243-252.
Points to consider in seeking biosafety approval for research, testing, and environmental release of experimental genetically modified biocontrol products during research and development
Background
Novel genetically modified biological control products (referred to as “GM biocontrol products”) are being considered to address a range of complex problems in public health, conservation, and agriculture, including preventing the transmission of vector-borne parasitic and viral diseases as well as the spread of invasive plant and animal species. These interventions involve release of genetically modified organisms (GMOs) into the environment, sometimes with intentional dissemination of the modification within the local population of the targeted species, which presents new challenges and opportunities for regulatory review and decision-making.
Tonui, W. K., Ahuja, V., Beech, C. J., Connolly, J. B., Dass, B., Glandorf, D. C. M., … & Romeis, J. (2022). Points to consider in seeking biosafety approval for research, testing, and environmental release of experimental genetically modified biocontrol products during research and development. Transgenic Research, 31(6), 607-623.
Analysis and control of Aedes Aegypti mosquitoes using sterile-insect techniques with Wolbachia
Background
Combining Sterile and Incompatible Insect techniques can significantly reduce mosquito populations and prevent the transmission of diseases between insects and humans. This paper describes impulsive differential equations for the control of a mosquito with Wolbachia. Several interesting conditions are created when sterile male mosquitoes are released impulsively, ensuring both open- and closed-loop control. To determine the wild mosquito population size in real-time, we propose an open-loop control system, which uses impulsive and constant releases of sterile male mosquitoes. A closed-loop control scheme is also being investigated, which specifies the release of sterile mosquitoes according to the size of the wild mosquito population. To eliminate or reduce a mosquito population below a certain threshold, the Sterile insect technique involves mass releases of sterile insects. Numerical simulations verify the theoretical results.
Chinnathambi, R., & Rihan, F. A. (2022). Analysis and control of Aedes Aegypti mosquitoes using sterile-insect techniques with Wolbachia. Mathematical Biosciences and Engineering, 19(11), 11154-11171.
Gene drive mosquitoes can aid malaria elimination by retarding Plasmodium sporogonic development
Background
Gene drives hold promise for the genetic control of malaria vectors. The development of vector population modification strategies hinges on the availability of effector mechanisms impeding parasite development in transgenic mosquitoes. We augmented a midgut gene of the malaria mosquito Anopheles gambiae to secrete two exogenous antimicrobial peptides, magainin 2 and melittin. This small genetic modification, capable of efficient nonautonomous gene drive, hampers oocyst development in both Plasmodium falciparum and Plasmodium berghei. It delays the release of infectious sporozoites, while it simultaneously reduces the life span of homozygous female transgenic mosquitoes.
Hoermann, A., Habtewold, T., Selvaraj, P., Del Corsano, G., Capriotti, P., Inghilterra, M. G., … & Windbichler, N. (2022). Gene drive mosquitoes can aid malaria elimination by retarding Plasmodium sporogonic development. Science Advances, 8(38), eabo1733.