Florida's Plan to Release GM Mosquitoes

this episode of real science is brought to you by curiosity stream sign up today at curiositystream.com real science and get free access to watchnebula.com [Music] it's the one thing everyone can agree on mosquitoes are the worst for some they are simply the ruiner of picnics and camping trips but for a huge fraction of the world they are much more than a nuisance mosquitoes cause more human suffering than any other organism because of the horrific diseases they carry over a million people worldwide die from mosquito-borne diseases every year in a previous video i talked about malaria perhaps the most devastating of all the mosquito-borne illnesses killing about half a million people each year and while less common other diseases like west nile virus yellow fever and dengue fever are each insidious in their own way debilitating and deadly to many in the tropics and subtropics some diseases like malaria are declining but other diseases like dengue are very much on the rise in the past 30 years the worldwide incidence of dengue has risen 30-fold billions get spent trying to combat these diseases vaccines insecticides education programs bed nets treatment drugs prevention drugs there are so many things scientists do to try to stem the tide of infections but even as progress is made in one region infections will flare up in others it's like the worst game of whack-a-mole imaginable it takes an unprecedented coordinated effort across many geographic and political lines to even make a dent and an insane amount of money but much of the current funding has plateaued and some of the drugs that have been used for years are becoming less and less effective the malaria parasite in particular has started to develop resistance to currently available drugs insecticide resistance is also becoming a challenge in many mosquito species including the widespread and usually invasive aedes egypti and this is why some scientists are looking towards a totally new approach something radical and controversial to end the whack-a-mole game once and for all genetically modified mosquitoes in theory their widespread release could lead to the total extinction of certain species of mosquitoes eliminating the vector for so many deadly diseases it's an extreme idea but a future with gm mosquitoes flying freely in our world may not be that far away this summer genetically modified 80s egyptian mosquitoes could be released in the u.s for the first time in florida and in texas so is this a sudden jurassic park experiment or the logical next step in controlling mosquito-borne illness in may of this year the epa in the state of florida unanimously approved an experimental use permit for millions of gm mosquitoes to be released in the florida keys for a landmark project the mosquitoes are genetically modified male 80s egypti mosquitoes known as ox-5034 branded as friendly tm mosquitoes developed by the company oxitec aedes aegypti are an invasive species in most places they exist originally from africa they have spread worldwide to almost every tropical and subtropical area they are often described as the cockroach of mosquitoes they thrive specifically living around people and are hard to get rid of they lay their eggs in any container they can find like inside of a clogged gutter a toilet tank a flower pot or discarded bottles or bottle caps making it hard to get a handle on their spread they can bite multiple people during their lifespan creating a huge potential to spread viruses and unluckily for humans they carry so many horrible ones zika the microcephaly causing virus and dengue often called break bone fever for how painful it is are some of the worst ones they carry and this is why the adc gypti mosquito has been targeted as a candidate for the gm technology at the heart of the so-called friendly mosquito is something called a self-limiting gene it starts with 80s egyptian mosquito eggs which are injected with short pieces of dna that contain the self-limiting gene sequence along with a fluorescence gene that acts as a marker this lethal gene is a tetracycline transcriptional activator variant or ttav gene once introduced into the mosquito's genome it encodes a protein that blocks transcriptional machinery for several other genes that are essential to mosquito development so without essential genes being expressed the mosquito larvae die before becoming adults but simply injecting the t-tav gene into these eggs would only be useful in killing the handful of mosquitoes you give it to hardly an economical way to kill off the trillions of mosquitoes that exist in the world for the gene technology to be useful the mosquitoes need to be able to pass the lethal gene down to their offspring and for this reason the lethal gene has a corresponding antidote to keep the mosquito larvae with this lethal gene alive they can be given tetracycline a common antibiotic the lethal t-tav protein cannot block the transcription of the other essential mosquito genes when it's bound to tetracycline this can therefore keep the gm larvae alive until adulthood when the gene is no longer lethal so in the lab mosquito eggs are injected with the self-limiting gene and the gm mosquito larvae are then reared in water containing tetracycline this way they can develop normally into adult mosquitoes then when adult gm mosquitoes are released and breed with wild non-gm mosquitoes their offspring inherit the lethal t-tav gene and without tetracycline in their environment they don't survive into adulthood over time and with enough gm mosquitoes released this technology has the ability to hugely suppress the numbers of mosquitoes in the wild and to make the technology even more powerful scientists recently found a way to ensure that the lethal gene only kills the female offspring because of this one copy of the t-tav gene remains in some of the male offspring of the injected mosquitoes who can then pass it on to some of their offspring this allows the gene to kill more mosquitoes across multiple generations until it eventually disappears from the gene pool after about 10 generations if effective this friendly mosquito technology could almost completely protect communities from dengue yellow fever zika and other mosquito-borne illnesses carried by the adc gypti mosquito without needing insecticides and the hope is that soon this same technology could be applied to any of the most damaging mosquito species including the anopheles mosquito that carries malaria the newest iteration of the technology is what is slated to possibly be tested in florida at the end of the summer in texas soon after that but if these trials go ahead they will not be the first time gm mosquitoes have been tested in the wild previous generations of the technology have already been tested with field trials taking place in panama the cayman islands malaysia and perhaps most significantly brazil [Music] the field trials in brazil began in 2011 with the first generation of the friendly mosquito technology ox-513a the studies were conducted in the semi-arid northeast of brazil in suburbs with a huge amount of dengue adc gypdy thrived there due to the amount of stored water and a high human population and thus provided the perfect place to test the technology male mosquitoes with the lethal gene insertion were dispersed in the study area by opening release devices through the window of a moving car these mosquitoes then went on to mate with the local population of females and their offspring having inherited the ttav gene could not survive oxitec reports that in this study the local 80s egypti population was reduced by 80 to 95 percent after a year of consistent releases some critics of the study claim that the suppression of mosquitoes was more like 60 to 70 but even still that is far better than traditional methods like insecticide spraying which rarely achieve much more than 50 suppression since then oxitec has also tested their second generation of friendly mosquitoes ox-5034 in brazil and achieved a similar result with reports of up to 98 suppression in just a 13-week window and this is the same technology that has been granted an experimental use permit for field trials in florida and texas these places don't currently have devastating mosquito-borne disease outbreaks like many places in the tropics but dengue and zika have both worryingly popped up in these places in recent years health officials are trying to keep these diseases at bay and their occurrence is an ever-present possibility and while the results from the field trials so far have been promising the question on everyone's mind is is it safe experiments with gm mosquitoes are often compared to jurassic park implying that these experiments could lead to drastic out of control and dire outcomes that releasing these mosquitoes could open an unforeseen pandora's box that we cannot close again and while yes it is impossible to foresee every outcome the technology can be assessed with what we know about it and what we know about genetics in general the main risk that opponents of this technology want to avoid is the potential for harm to humans an important and valid concern critics claim that there is a risk that the genes from the gm mosquito could be transferred to humans or other animals that have been bitten but a gm mosquito biting a human is unlikely to begin with because only the females bite and the females are engineered to die but in the unlikely event that some females do survive and do bite people the transfer of genetic material from mosquito to human just doesn't happen gmo or not mosquitoes have been feeding on humans for more than a hundred million years by assessing the genomes of humans and many mosquito species we can see that there is no evidence of gene transfer via blood feeding even if this hypothetically were to occur even at extremely low frequencies we would be able to see dna sequences from human feeding mosquitoes in humans and from bird feeding mosquitoes and birds and so on and the reverse is also true even if animals consume the gm mosquitoes animals do not incorporate dna from their food into their genome gmo or not numerous studies have shown that livestock or chickens that eat gm corn for example do not have any trace of the genetic material in their bodies after eating it horizontal gene transfer like this is a commonly cited worry and it should definitely continue to be studied rigorously but with all the information we have so far it seems like this scenario is extremely unlikely other risks that critics cite are the potential impacts on the environment the first that comes to mind for many people is if we kill off the mosquitoes will this harm the food chain will it leave the birds frogs and other animals with less to eat this would certainly be a major concern if we were to eradicate all species of mosquitoes across the globe for reference there are 3 500 different species of mosquitoes around the world and 80 species that occur in florida and 85 in texas but the studies being proposed in florida and texas only focus on one species the adc gypti which is also an invasive species in both places and because it's non-native to the area it has not co-evolved with other organisms in the ecosystem and is not a keystone species that other animals need for food one day if we do want to kill off all of the disease-carrying mosquitoes this question will need to be studied more carefully but even still of the 112 genera of mosquitoes just three bear the primary responsibility for the spread of human diseases there are so many factors that go into trying to assess the risks of a new technology like this and i can't begin to address them all here if you want to read more about the risk assessments done there is a 140-page document addressing many of the concerns put forth by the public concerning auxitex gm mosquitoes which i will link below oxitec has gone through a lot of rigorous testing to try to make sure their technology is safe but you can never be a hundred percent sure that it's foolproof and this is where all the debate comes in a previously planned release in the florida keys of an earlier version of oxitec's gm mosquito was withdrawn after a referendum indicated significant opposition from local residents and more recently the public forum on oxitec's recent permit application garnered 31 000 comments opposing release and 56 in support and before the study can go ahead it needs final approval by the mosquito control district and it is not a sure thing that that will happen many people do oppose testing this technology without understanding the first thing about it but some of the concerns with the bias of oxitec's risk assessment are valid yes the research oxitec is doing needs to be transparent with lots of independent research done to remove any bias but ultimately a new technology to fight mosquito-borne illness is desperately needed and this looks like it could one day provide the solution that the million dead people per year probably wished they had our modern world is increasingly being shaped by our understanding of genetics with major breakthroughs in gmos and gene editing in recent years in the next video i will talk about crispr and how it is already reshaping how we think about disease genetic advances like this are extremely complex and inherently come with a lot of uncertainty and therefore a lot of controversy but genetic engineering is going to be in our futures if you want to learn more about genetics then you should sign up for curiosity stream curiosity stream is a streaming platform that has thousands of high quality high budget documentaries like this one called dynamic genomes which explores how the junk part of our dna may actually work to decide our personal characteristics and tendencies it's a great overview of how mysterious and complicated our genetics really are but 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Channel: Real Science

Views: 276,209

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Id: RrIS7mia36k

Length: 16min 26sec (986 seconds)

Published: Sat Aug 01 2020