Seite - 101 - in Critical Issues in Science, Technology and Society Studies - Conference Proceedings of the 17th STS Conference Graz 2018

application of gene drives against agricultural pests in numerous other cases. Followed by not only ethical but also ecological implications. Medea is named after the sorceress from Greek mythology, the wife of Jason, who is known for his quest for the Golden Fleece. And as Medea found out that Jason was cheating on her, she intended to punish Jason by killing the children that she had with him. The name seems to meet the mode of action of the gene drive, as the technique genetically makes the mother kill their offspring. The genetic construct contains a tightly linked maternal toxin and an embryonic antidote. Therefore, embryos of Medea mothers are killed if they did not inherit the Medea construct. And surviving embryos will continue inheriting the gene drive [6]. In principle, Medea can be characterized as a low threshold gene drive and a modification drive. Which means in its basic form it is not meant to eradicate a population but to invade and take over. And low threshold means that it does not take many Medea-carrying organisms to drive the trait into the population. Therefore migration of those flies is a problem because – at least theoretically – one gene drive might eliminate all spotted-wing fruit flies in California and beyond. Malaria and Dengue An example of potential gene drive applications in the field of infectious diseases aims at vector species of pathogens such as for Malaria and Dengue. The malaria pathogens include 5 Plasmodium species. Wherein Plasmodium falciparum is the main contributor. The malaria vectors are mainly three species of the Anopheles genus. According to the World Health Organization (WHO) malaria is considered endemic in 91 Countries. The WHO estimates that there have been 216 million new malaria cases in 2016 and almost half a million deaths, most of them children under 5 years of age [7]. Strategies of disease control are hindered by emerging resistances of the vector against insecticides and of the pathogen against drugs [7]. Dengue on the other hand is transmitted by the dengue virus of which 4 different serotypes exist. The main vector species are of the Aedes genus. Dengue is endemic in approximately 100 countries. It is estimated that there are around 93 million clinical cases each year and around 22,000 deaths, also mostly children. The treatments remain supportive and mostly preventive vector control is condoned [8], [9]. Regarding malaria, there is the Target Malaria Project which is funded by the Bill and Melinda Gates Foundation and the Open Philanthropy Project Fund. Target Malaria pursues two gene drive approaches to tackle the malaria vector. One is the supposedly Y-linked X-Shredder approach. The letters X and Y of course stand for the sex chromosomes. In this approach, the male specimen produces mostly Y-bearing sperm and if such a male mates a wild type female, male-biased sex ratios of up to 95% can occur in which all males are also X-Shredder males [10]. After a few generations the increasing imbalance leads to a population crash. The X-Shredder technique constitutes a suppression drive. There is the danger that such a gene drive may spread to surrounding populations, which seems especially probable in a population with a low ratio of females. The approach might favor alternative vector species. Since wiping out one mosquito population may trigger the next vector species to fill the ecological niche. Also it might trigger a coevolution of the pathogen. As there are fewer females to bite humans, it becomes more important for the pathogen to be even more virulent. But the most harm-bearing vulnerability is that there are no corrective actions to reverse or limit an X-shredder gene drive once released. It is however theoretically possible, although rather unlikely that a resistance will 101