Cane Toad on Grass. Image from SamFraser-Smith, National Wildlife Federation, www.nwf.org

Cane Toad on Grass. Image from SamFraser-Smith, National Wildlife Federation, www.nwf.org
A recent publication from Harvard scientists outlines the potential of a cutting-edge technology, CRISPR, to improve on an old technology called Gene Drives in order to solve the enormous problems caused by invasive species. However, attempts to control harmful species with this technology may just be another way to introduce potentially destructive foreign elements into an ecosystem. Furthermore, relying on genetic sequences of wild organisms that are constantly evolving in ways we cannot predict, the technology may not work as it was intended to.

The scientists explain that CRISPR-controlled Gene Drives could modify the genomes of invasive or harmful species such as disease-carrying mosquitos, modifications, which could spread throughout an ecosystem and selectively eliminate “pests”. The authors show significant forethought and humility by calling upon ecological, ethical, and engineering experts to discuss the benefits and dangers of this work, before it’s unleashed upon the world.

Introducing a non-native organism in order to eliminate a biological pest has been unsuccessfully deployed several times before. For example, cats were introduced to Marion Island in order to reduce the mouse population, and the cane toad was introduced to Australia to eliminate the cane beetle. The cats, which had no natural predators, expanded their population greatly, and have severely endangered the Marion Island bird population. The cane toad, a prolific breeder, has increased its population to astounding numbers, and unfortunately produces a toxin that kills native animals in addition to the cane beetle. CRISPR-controlled Gene Drives may perpetuate these types of problems.

Aside from the ecological concerns, the technology may not actually work. CRISPR is a powerful genome-editing technology that has been researched extensively in model laboratory organisms over the past two years. However, getting the technology to work in wild organisms poses a significant challenge since the genetic code of wild organisms is constantly changing, many times unpredictably. As the technology relies on its ability to recognize specific genetic sequences that could change over time, the technology might become ineffective or cause an unanticipated effect.

Many thanks to Jonathan Kotula, post-doc in the Department of System Biology and the Wyss Institute, for providing expert commentary on the topic. Edited by Ankita Shastri.

From Genetic Engineering to the Rescue Against Invasive Species (original article here)

For more information on genetic engineering, see the following SITN articles:
“Genetically-Modified Organisms: The good, the bad, and the future” Link to the original article
“Super nanners! Engineering bananas to save vision, life in East Africa” Link to the original article
“Genetically modified yeast and Science Fiction” Link to the original article

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