Gene Drives

Introduction

Cutting-edge genetic technology is finally breaking the conventional rules of evolution–but how exactly? Gene drives have raised both excitement and concerns as groundbreaking research is being made about its applications. Formally, gene drives are defined as systems of biased inheritance where preferable genotypes are increased through specific genetic elements. This can occur naturally, which are often called “selfish genes,” or synthetically. In any case, gene drives can have wide-ranging impacts on evolution and ecosystems.

How do Gene Drives Work?

The goal of gene drives is to increase the chances that the offspring will inherit a genotype to more than 50%. This will impact evolution because the genotype will show up more in the population over time. Therefore, Gregor Mendel’s conventional rule that an offspring will have an equal chance at inheriting two different genotypes is completely changed through the process of gene drives. 

Moreover, gene drives are most commonly developed in a laboratory through CRISPR/Cas9. These have led to researching with organisms such as mosquitoes and fruit flies to not only understand how gene drives work under different environmental conditions, but also how they affect a wide variety of organisms. One known natural or “selfish” gene drive is the Homing Endonuclease gene, found in fungi and bacteria. It rapidly spreads  the drive allele through populations  because individuals that are heterozygous for a drive allele are turned into homozygotes through “homing,” a process where they spread by cleaving a homologous wild-type chromosome and copying themselves into the cut site through homology-directed repair. Using similar processes, synthetic and natural gene drives work to spread a genotype further through populations than expected.

Types of Gene Drives

There are two distinct ways in which a Gene Drive can spread: modification drives and suppression drives. Modification drives are when the altered allele is spread by “hitchhiking” with the drive to wild-type chromosomes. This essentially means that the favorable trait is spread and shown as a specific phenotype through generations. On the contrary, a suppression drive is when a genetic alteration that reduces population size is spread to more evidently show the favorable genotype. However, both of these methods have the same goal of spreading out a particular allele. 

Applications of Gene Drives

One of the most prevalent ways that gene drives are used is to address public health threats in our community. For example, a case study by the National Institutes of Health demonstrates how CRISPR/Cas9-based gene drives in Anopheles gambiae mosquitoes reduce the spread of human malaria in Sub-Saharan Africa. In fact, malaria and other illnesses such as Lyme disease stand at the most pivotal point for research today, and gene drives are currently helping address such concerns in third-world and underprivileged communities. Similarly, its ability to protect endangered species can be a game-changer for wildlife conservation techniques.

Another way that gene drives are used is for protection or conservation of vital organisms — such as eliminating populations of the non-indigenous mouse, Mus musculus — to protect native biodiversity on islands around the world. They can also work to protect  ecosystems at-risk from the spread of destructive invasive species and improve sustainability in agriculture by reducing the need for and toxicity of pesticides and herbicides. Such ways in which gene drives help facilitate preservation is exactly why scientists are hoping to continue researching its impact on entire ecosystems. 

Ethical Considerations and Risks

Although gene drives pose a promising future for our community, one must consider its holistic ethicality. Scientists themselves emphasize that the development of gene drives and such technology must include robust safeguards and methods of control. Moving too quickly can result in missing crucial experimentation that can eventually cause holes in research or even harm to organisms. Therefore, proper trials and tests must be put into place to ensure safety from the unknown potential of gene drives. 

Conclusion

As gene drive technology continues to expand in the world of science, it offers ways

in which we can transform our community for the better through public health and conservation efforts. Its ability to redesign populations and save organisms is both fascinating and promising. Still, its power to alter ecosystems can introduce possible risks that should not be overlooked. It is necessary to ensure that careful research is carried out and that gene drives are developed with caution in ways that truly benefit society.

References:

Drive, Gene, et al. “Introduction.” Nih.gov, National Academies Press (US), 28 July 2016, www.ncbi.nlm.nih.gov/books/NBK379282/ “Gene Drives.” Wyss Institute, 13 Mar. 2019, wyss.harvard.edu/technology/gene-drives/

‌Roberts, Rebecca. “Synthego | Full Stack Genome Engineering.” Www.synthego.com, 9 Aug. 2022, www.synthego.com/blog/gene-drive-crispr#gene-drives-the-basics.

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Collins, James P. “Gene Drives in Our Future: Challenges of and Opportunities for Using a Self-Sustaining Technology in Pest and Vector Management.” BMC Proceedings, vol. 12, no. S8, July 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC6069294/, https://doi.org/10.1186/s12919-018-0110-4.