A somatic cell that contains nuclei derived from genetically different sources. The nuclei do not fuse, but divide individually and simultaneously to form new cells, as commonly occurs in fungal hyphae. Ciliate protozoans, such as Tetrahymena, may be functional heterokaryons, if they carry a drug-resistant gene in the transcriptionally inactive, diploid, germinal micronucleus and a drug-sensitive allele in the transcriptionally active, highly polyploid, somatic macronucleus. See interspecific heterokaryon.
Subjects: Genetics and Genomics.