In 2016, the Department of Life Sciences at Imperial College London produced a scientific paper on the use of CRISPR-cas9–a controversial technology with the ability to alter DNA and edit genomes–in malaria-transmitting mosquitoes. As is mentioned in the study: “A CRISPR-Cas9 gene drive system targeting female reproduction in the malaria mosquito vector Anopheles gambiae.”

Cas9 is a protein enzyme that has the ability to cut foreign DNA. In earlier studies, scientists determined that it could be adapted, and controlled, allowing for more recent controversial topics, such as the CRISPR gene-edited twins in China. This can be done in two ways. The first method, non-homologous end joining, calls for the use of Cas9 to cut into DNA and then “gluing” the the two cuts back together. The second method, which is mentioned in the study, also uses Cas9 to cut into DNA, then inserts attP-GFP–described as the docking cassette–which is meant to produce a null phenotype.

Essentially, this allows for the controlled manipulation of A. gambiae’s reproductive system in female mosquitoes, making them unable to reproduce. Malaria is only transferable through female mosquitoes, which would ultimately help eliminate a significant portion of the mosquito population over a short segment of time, allowing for their eventual extinction.

Throughout human history, the topic of man-based extinction has been an important area of discussion. More importantly, the ethics of choosing which species should exist and which should not. The same rule of law should be applied in the discussion of mosquitoes. What is more significant that the direct impact that this will have are the adverse effects. As with any species, there is much we do not know about the role of mosquitoes as a prey and a predator. The ecosystem is sensitive to changes in existing life forms and the elimination of one species could disorient it in its entirety. These are some of the conditions that people must be mindful of. While malaria is severe, we must also consider the short- and long-term effects. It is not my decision, nor any other one person’s to make. Even this process of decision-making remains unclear, as mosquitoes frequently travel between borders, claiming many nationalities. If states such as China and Taiwan are unable to dispute territory in the South China Sea in a rational matter, the topic of selective gene manipulation of travelling mosquito populations will not be much easier.

The first article that I would like to bring to your attention is a study published in 2014 by Drs. Heidi Appel and Rex Cocroft. Their scientific study is quite fascinating, bringing forth new developments in our understanding of not only particular species of plants, but to some degree our ecosystem as a whole.

The report uses a plethora of scientific jargon that is commonly used in this area of study and throughout the paper. The first of these is playback. The playback describes the “music” or “sound” that the plant, Arabidopsis thaliana, is exposed to, In this case, it is designed based on the feeding behavior of the P. rapae Caterpillars. More specific to the plant itself are two of the main chemicals that are released as defense mechanisms: glucosinolates and polyphenol anthocyanins. According to the report, there is a strong negative correlation between between induced glucosinolates and caterpillar growth rate. Therefore, it can best be described as one of the means of defense. Anthocyanin is a naturally producing chemical in plants. However, as they are placed in stress-induced situations, the amount increases, giving the plant a more red-like color. The more stress, the more red.

The study indicates two potential hypothesis to help explain why playback of chewing vibrations resulted in the systemic priming of glucosinolates and anthocyanins. The first attributes this to the fact that vibrations propagate throughout the plant, hinting that these are used as an early warning system, resulting in the priming of systemic leaves. Alternatively, the vibrations in the playback leaf could have resulted in what could be akin to a domino effect. As that leaf is exposed to playback, it in turn produces a triggered systemic signaling in the form of airborne volatiles, phloem-borne signals, or electrical signals.

Appel and Cocroft do an excellent job in providing the details leading up to and during the experiment, constructing a solid foundation on which they continue to deliver their argument. That the vibrations produced by herbivory induce a chemical response that acts as a defense mechanism. They provide statistics regarding the conditions in which they controlled the temperature of the leaves, where they were acquired, and their age. The same is true for the caterpillars. The experiment is very well controlled.

Thanks for joining me!

Good company in a journey makes the way seem shorter. — Izaak Walton