New methods of genetic engineering can be used not only to change the structure of DNA, but also to enhance the frequency of new genetic information being passed on to following generations. So-called 'gene-drives' were developed specifically for this purpose. To establish a gene-drive, a nuclease ('DNA scissor') is introduced into the genome. The nuclease cuts the DNA at a specific site and inserts its own DNA into the genome. The process of genetic engineering is self-replicating in the following generations so that offspring will homozygously inherit the new genetic condition. This allows the artificial genes to spread much more rapidly throughout populations than would naturally be the case – and, in some circumstances, either completely change the biological characteristics of the whole species, or wipe them out.
Gene-drive is, in particular, intended to alter wild species, whereby the application is purposely not restricted to the field or the laboratory. One reason for the introduction of a gene-drive could be the decimation of populations of specific species. In these cases, the nuclease can be used to damage an important site in the genome so that only male offspring survive. There are currently ongoing discussions about whether such methods should be used in insects, undesired wild life animal species or weedy plant species. A further application could be to change genetic information in a way that alters the biological characteristics of a species e.g. to manipulate mosquitoes so that they no longer transfer malaria, or make weedy species more vulnerable to herbicides.
What is the problem?
Experiments showing that a gene-drive can be established in insects provoked huge controversy amongst scientists. Many experts are warning against the release of any of such organisms into the environment. Our current level of knowledge does not allow us to make reliable predictions about how such an organism will interact with the environment, or how to prevent environmental hazards. Once released, organisms inheriting a gene-drive can substantially damage ecosystems. There is no reliable method of controlling, or reversing such releases.
Throughout history mankind has bred plants and animals, in particular, for agricultural purposes; some of which are genetically engineered. Now, however, with gene-drive, a tool has been developed that can be used to genetically engineer wild species, and which can ultimately lead to the manipulation of the 'germline' in biodiversity. Human intervention has already led to the unintended extinction of many species. So the ethical question arises of whether we should allow the indiscriminate genetic manipulation of wild species, or even to eradicate them according to our interests and needs.
The underlying problem is not completely new: We already know that several genetically engineered plants have escaped into populations of wild relatives. And, as yet, there is simply insufficient regulation to prevent such uncontrolled spread.