SATURDAY, 11 OCTOBER 2014
Gendercide of Mosquitoes
Genetically engineering a population of mosquitoes to produce only male offspring could provide a novel means of eliminating malaria. Researchers have developed a method of selectively destroying the X-chromosome in mosquito sperm, so that only the male-producing Y-chromosome was available during fertilization. The number of offspring produced remained unaltered, but were more than 95 per cent male. Malaria is a potentially lethal disease caused by the parasite Plasmodium falciparum, which only reproduces in the gut of the female Anopheles mosquito. Female mosquitoes are also solely responsible for transmitting malaria to people as they feed on blood; male Anopheles mosquitoes are vegetarian. Altering the sex ratio in mosquito offspring has two benefits for malaria control. Firstly, the number of females available for reproduction and transmission of malaria is reduced. Secondly, over a number of generations, the reproductive capacity of the mosquitoes diminishes as the proportion of females available for breeding becomes unsustainable. Because mosquitoes have only a short lifespan of one to four weeks, the impact of changing population dynamics is rapidly observable. Unlike other methods of controlling mosquito populations, this technique specifically targets Anopheles mosquitoes.
It does not impact other insect populations, or require environmental engineering or interventions by the local human community. There are significant social and political barriers to overcome before the system can be implemented outside the lab. Though, given the numerous benefits, approval will hopefully be forthcoming.Madeline Kavanagh
Are we comfortable with our innermost thoughts?
How far would you go to escape the queasy feeling that often accompanies self-reflection? As far as electrocuting yourself? It might sound surprising, but research by a team at the University of Virginia indicates that 67 per cent of males and 25 per cent of females would rather self-administer a small electric shock than sit alone with their thoughts for as little as 15 minutes. The team wanted to determine how easily people were able to disengage from the distractions of modern life and how pleasant they found the experience. Students were asked to sit for between six and fifteen minutes in either a distraction-free lab or home environment and “just think”. About 50 per cent of participants found the experience uncomfortable, rating it at or below the mid- point on an enjoyment scale. The majority complained of feeling unable to concentrate and that their mind wandered. Prompting the participants to think about a specific subject or upcoming holiday did not improve task enjoyment. Researchers then tried to determine if experiencing an unpleasant sensation, such as an electric shock, was preferable to doing nothing at all. The result, for men at least, was a resounding yes. The observed gender difference was attributed to the ‘sensation- seeking’ behaviour of men and the lower pain threshold of women. Inward thinking is a uniquely human trait thought to be important in creativity, and engaging in mindfulness on a regular basis is linked with improved mental health. However, despite these clear benefits it’s now clear that “the untutored mind does not like to be alone with itself ”. Madeline Kavanagh Recent studies published by Professor Scott Steffensen and his collaborators at Brigham Young University suggest that addiction is a chronic brain disease, not just a result of bad choices or rebellious behaviour, and that it could be treated and possibly cured like any other disease. The team strongly believes that in the near future, medicine will be able to help addicts return to a relatively normal state by dealing with the changes in their brains.The studies show that there is a common mechanism behind addiction to nicotine, alcohol, and drugs which is comparable to a driver overcorrecting a vehicle. So, how does it work? The presence of these substances in a human’s body triggers the release of unnaturally high levels of a hormone called dopamine in the brain’s pleasure system. That, in turn, leads to an occurrence of oxidative stress in the brain. The body tries to deal with, and compensate for, the unnatural levels of the hormone by producing a protein called brain derived neurotrophic factor (BDNF) which suppresses the brain’s normal production of dopamine. The only problem is that the correction occurs long after the person comes down from a high. Thus the body’s delayed reaction results in a lack of dopamine, which has unpleasant consequences commonly known as withdrawal symptoms: anxiety, distress and pain. Steffensen and his collaborators emphasise how misunderstood the concept of addiction is in our society and how they hope their studies will help to better explain it as well as grasp the mechanisms behind it. These studies could be a milestone in helping to eliminate the stigma that haunts addicts and to help them to return to society. Paula Siemek