This release is available in German.
Genetically modified animals are designed to contain the spread of pathogens. One prerequisite for the release of such organisms into the environment is that the new gene variant does not spread uncontrollably, suppressing natural populations. Scientists at the Max Planck Institute for Evolutionary Biology in Pln, Germany, have now established that certain mutations are maintained over an extended period if two separate populations exchange individuals with one another on a small scale. The new gene variant may remain confined to one of the two populations. The migration rate between the populations determines how long the new gene variant is expected to survive in the environment. These new findings may help to achieve greater safety when conducting release experiments involving genetically modified animals.
Genetically modified organisms must not be allowed to spread uncontrollably. Scientists are therefore keen to take advantage of a mechanism that will localise the spread of mutants. Mutants with a heterozygote disadvantage, as it is known, reduce the evolutionary fitness of their carriers to varying degrees if they are only available to one gene copy (heterozygote) or exist in both gene copies (homozygote). In their study, the Max Planck scientists assumed a fitness loss of 50 percent (compared to wildtypes) for mutant heterozygotes and a 10 percent fitness loss for mutant homozygotes.
A mutant with a heterozygote disadvantage can be maintained in a population if it occurs frequently enough for sufficient homozygote offspring to be produced. Above this value, it can suppress the non-mutated gene variant completely and the mutated form becomes extinct. Populations containing mutants with heterozygote disadvantage develop into one of two stable states. These mutant types therefore seem to be we
|Contact: Dr. Philipp M. Altrock|