Health Security

Facilitating the Conversation: Gene Drive Classification

Facilitating the Conversation: Gene Drive Classification

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J. Overcash and A. Golnar,  Health Security,  2021.

Gene drives are an emerging technology with tremendous potential to impact public health, agriculture, and conservation. While gene drives can be described simply as selfish genetic elements (natural or engineered) that are inherited at non-Mendelian rates, upon closer inspection, engineered gene drive technology is a complex class of biotechnology that uses a diverse number of genetic features to bias rates of inheritance. As a complex technology, gene drives can be difficult to comprehend, not only for the public and stakeholders, but also to risk assessors, risk managers, and decisionmakers not familiar with gene drive literature. To address this difficulty, we describe a gene drive classification system based on 5 functional characteristics. These characteristics include a gene drive’s objective, mechanism, release threshold, range, and persistence. The aggregate of the gene drive’s characteristics can be described as the gene drive’s architecture. Establishing a classification system to define different gene drive technologies should make them more comprehensible to the public and provide a framework to guide regulatory evaluation and decision making.

Gene drive architecture and classification. (A) Gene drives can be broken down into 5 functional characteristics. (B) These functional characteristics can be organized in any number of different ways to create a variety of gene drive architectures. (C) Gene drive architectures can be used to classify different instances of gene drives. Here, we provide 3 hypothetical gene drive classifications. Example 1 (Kyrou et al15) is a low-threshold suppression drive that utilizes CRISPR/Cas9 to drive replication. The drive also has the characteristics of being unrestricted and self-eliminating. Example 2 (Buchman et al8) is a high-threshold, replacement drive that utilizes an interference mechanism to inhibit embryonic development and would likely be classified as a localized and self-sustaining. Example 3 (Maselko et al31) is a high-threshold, localized, underdominance drive, that can be further classified as localized and self-sustaining. Classification selections that have a higher level of uncertainty are distinguished with an asterisk (*)