Heterokaryon

This can occur naturally, such as in the mycelium of fungi during sexual reproduction, or artificially as formed by the experimental fusion of two genetically different cells, as e.g., in hybridoma technology.

[2] Heterokaryons are found in the life cycle of yeasts, for example Saccharomyces cerevisiae, a genetic model organism.

This has two types of cell nuclei, a large, somatic macronucleus and a small, germline micronucleus.

Both exist in a single cell at the same time and carry out different functions with distinct cytological and biochemical properties.

These nuclei do not immediately fuse, and remain haploid in a n+n state until the very onset of meiosis: this phenomenon is called delayed karyogamy.