In Bond with Selfish Genes
How Gene Drives can help fight pests and pathogens.
For a number of years, the media has been reporting more and more about so-called gene drives – and reporting astonishing things. It is said that gene drives could be used to render entire populations of disease carriers completely harmless or to eradicate them. It might even be used to destroy species. The method is discussed again and again, especially with regard to malaria mosquitoes. What to make of it? What is Gene Drive, what can be achieved with it - and what not?
Gene Drive, also known as "Genturbo" in German, is often presented as an innovative genetic engineering process, but it is not a new invention by molecular biologists. Rather, it is a naturally occurring phenomenon with certain genes acting in a selfish manner, overriding the Mendelian rules of inheritance and enlisting in disproportionate numbers of offspring.
In an organism with the usual double ("diploid") set of chromosomes, a certain gene is usually present in two variants, the "alleles". These are usually slightly different from each other. One of the alleles comes from the mother, the other from the father. During sexual reproduction, an organism only passes on one of its two alleles to its offspring – which one usually depends on chance and is rolled out anew with each mating act. On average, half of the offspring will get one allele and half will get the other. Therefore, in the absence of selection pressure, the frequency of a particular allele in a population does not typically change. However, if one of the alleles exhibits "drive" behavior, it is found in a disproportionately large number of offspring (in the extreme case in all) and thus displaces its counterpart. The drive allele is thus "driven" into the population.
How does it work? …