Engelsk definition
A naturally occurring reproductive phenomenon of INVERTEBRATES in which only certain combination of crosses result in viable embryos due to incompatibility between sperm and egg cells that is caused by differences in intracellular parasites (symbionts). For example, a maternally inherited symbiont bacteria, e.g., WOLBACHIA, induces changes in sperm of the host, causing mitotic defects in the fertilized embryo only in crosses between symbiotic males and females harboring a different or no symbiont.