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  • Writer's pictureSwaha Chakraborty

GM Mosquitos and Gene Drives: Defying Nature

Of the many insects which plague our planet, mosquitoes continue to be one of the biggest threats to public health. Millions of cases each year stem from diseases such as dengue fever, malaria, yellow fever, and the zika virus. Mosquitos are responsible for the deaths of more than 700,000 people a year, which is more than any other animal. Even though we have successfully decreased the number of deaths through the use of insecticides, vaccines, and pharmaceutical treatments, mosquitos continue to be a threat. This threat has become even more noticeable since the insects have begun demonstrating resistance to insecticides.

Yet again, genetic engineering promises a quick solution to the obstacles nature has thrown our way. Since only female mosquitos can transmit diseases to humans, scientists are looking for ways to control the female population. CRISPR technology allows for us to genetically engineer a mosquito with a gene that affects its reproductive fitness. Once released into the wild, this GM mosquito can introduce the gene to a population of mosquitos, effectively disrupting reproduction within that group. This is done by either altering sex chromosome inheritance in a way that causes the majority of offspring to be male, or disrupting female fertility genes to prevent them from laying eggs altogether.

Under natural circumstances, two sexually reproducing organisms will pass on their traits in a way that allows their offspring to have approximately fifty percent of its DNA from "parent A", and the other fifty percent from "parent B". A gene drive is a system that grants a specific trait a greater chance of being passed down to offspring. This means that the gene's prevalence in the population will also be enhanced. It is that technology that scientists are now utilizing to make deadly mosquito populations favor traits such as infertility or preference for male offspring. Since genes that cause infertility would not be favorable under the laws of natural selection, and would quickly die out in nature, engineered gene drives are crucial to helping these mutations survive.

However, we must also be cautious of the ethical and scientific implications. From a social health standpoint, eliminating a major source of disease would benefit the safety of everyone. Yet, altering the genome of an organism and then releasing them into the wild is a scientific hazard in and of itself. The mutated mosquitos could then cause the species to evolve in a way that generates new, unknown diseases. We must also remember that humans come in contact with these insects on a fairly frequent basis. There has to be a proven guarantee that exposure to mosquitos (being bitten by one, inhaling one, or ingesting one) will not transfer any harmful genes to humans. Furthermore, artificially manipulating the gene pool of a living species raises its own questions. Are we qualified to make decisions that have always been in the hands of nature?


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