Heterokaryon incompatibility

Heterokaryon incompatibility is the inability of two strains to undergo fusion of vegetative fungal cells. This vegetative compatibility system is dictated by a series of heterokaryon incompatibility (het) loci whose alleles must all be identical for stable hyphal fusions to occur.  Het loci have been identified in several filamentous fungi, but are currently unknown in Aspergillus flavus and A. parasiticus