Keywords: Self sustaining

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. 2023-04-04 14:22:19.
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 want a gene drive to spread universally. If a gene drive were designed to cause the collapse of a pest population, it may inadvertently cause the collapse of the entire species. Migration is the mechanism through which a gene drive can spread to distant populations. Understanding its effect on the progression of a gene drive is crucial to our ability to control a gene drive. While migration can spread the gene drive to other populations, equally it can bring in other alleles to the population that may disrupt the progression of the gene drive. Through our deterministic migration gene drive model we can assess the conditions in which a gene drive is likely to spread to unintended populations, and if a gene drive is likely to be displaced by incoming alleles.Competing Interest StatementThe authors have declared no competing interest.

Genetic control of invasive sea lamprey in the Great Lakes

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D. Ferreira-Martins, J. Champer, D. W. McCauley, Z. Zhang and M. F. Docker,  Journal of Great Lakes Research,  2021-11-08 16:16:20.
The invasive sea lamprey was a significant factor in the collapse of fish stocks in the Great Lakes, and it continues to threaten the multi-billion-dollar fishing industry. Thus, substantial resources are invested annually on sea lamprey control. Current control strategies have reduced sea lamprey populations by up to 90%, but they are expensive and have some limitations, e.g., lamprey-specific biocides applied to larval habitat impact native lampreys, and physical barriers that block adult lamprey access to spawning habitat impede migration of other fishes. Therefore, genetic control options which offer a theoretically powerful and effective pest control tool are being explored, although they have uncertain sociopolitical support, especially given the need to protect sea lamprey in their native range in Atlantic drainages. Here, we present an overview of genetic approaches with potential for application to sea lamprey control in the Great Lakes. We classify these approaches into two major categories: self-limiting (heritable sex ratio ratchet, Trojan gene, split gene drive) and self-sustaining (gene drive-based sex ratio distortion, homing suppression gene drive, toxin-antidote gene drives, and modification-type gene drives to aid suppression). We describe the technical aspects, challenges, and potential application of each method, focusing on gene drives, a fast-evolving research area that was only a distant option for sea lamprey control in previous reviews. We conclude that, given the risk of undesired spread of deleterious alleles from the Great Lakes, self-limiting genetic control options and confined gene drives will likely be preferred over unconfined gene drive options for sea lamprey control.

Gene-Editing Approach To Control the Invasive Gray Squirrel

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M. Campbell,  Technology Networks,  2021-03-08 14:33:09.
Biodiversity refers to the extent of the variety of life that is found on planet Earth – and it is currently under threat. Changes in biodiversity have been flagged as "surpassing safe limits" for several years, and world leaders and scientists across the globe are consequently exploring different ways to address the crisis. Invasive species, defined by National Geographic as "an organism that is not indigenous, or native, to a particular area", threaten planet Earth's biodiversity to an even greater extent than climate change. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment Report found that the number of invasive species per country have risen by ~70% since 1970 across 21 countries that were included in the report. An example of an invasive species is the gray squirrel Sciurus carolinensis found in the UK, which outcompetes the native red squirrel for resources and habitats and carries diseases that are not pathogenic to themselves but can kill red squirrels.

Ecology: Gene drives may help control invasive grey squirrel in the UK

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A. Korn,  EurekaAlert,  2021-03-04 19:50:50.
Gene drives introduce genes into a population that have been changed to induce infertility in females, allowing for the control of population size. However, they face technical challenges, such as controlling the spread of altered genes as gene drive individuals mate with wild individuals, and the development of genetic resistance, which may render the gene drive ineffective. To address these challenges, Nicky Faber and colleagues used computer modelling to investigate the effectiveness of a combination of three gene drive technologies using the grey squirrel as a case study.

Genetically modified squirrels could curb growing population of greys

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S. Knapton,  Telegraph,  2021-03-04 16:06:59.
Mutant grey squirrels, genetically modified to spread infertility genes, could be released into the wild to tackle the burgeoning population,

Expert reaction to a paper suggesting that gene drives could be used to help control grey squirrel numbers in the UK

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Anonymous,  Science Media Centre,  2021-03-04 15:59:10.
This study assesses the prospects for using a gene drive to control invasive grey squirrels in the UK. This is a modelling study exploring the potential for such an approach – no such gene drives currently exist and developing them for grey squirrels would be quite a long-term project. Invasive species are a major problem for biodiversity and conservation; in many cases there are no adequate methods for control. Genetic methods may provide new options, potentially both more effective and with fewer off-target effects. Most work on gene drives has focused on mosquitoes; this study is unusual in focusing on a vertebrate (grey squirrel), though there has also been interest in targeting invasive populations of mice and rats on islands.

CRISPR gene drives may come to a squirrel near you.

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Anonymous,  NewsBeezer,  2021-03-04 15:48:43.
Today’s gene drive technologies could be blended to provide control of the invasive gray squirrel population in the UK – with minimal risk to other populations, according to a new modeling published in the journal Scientific reports. Gene driving introduces altered genes into a population that can cause infertility in women. This allows scientists to control the size of the population. However, this tactic faces technical difficulties such as controlling the spread of altered genes while certain animals that are part of the gene drive population mate with uncontrolled populations ̵

Novel combination of CRISPR-based gene drives eliminates resistance and localises spread

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N. R. Faber, G. R. McFarlane, R. C. Gaynor, I. Pocrnic, C. B. A. Whitelaw and G. Gorjanc,  bioRxiv,  2020-08-27 14:22:46.
We present HD-ClvR, a novel combination of CRISPR-based gene drives that eliminates resistance and localises spread. As a case study, we model HD-ClvR in the grey squirrel (Sciurus carolinensis), which is an invasive pest in the UK and responsible for both biodiversity and economic losses.