Heterocaryon

In nature, the formation of heterocaryons is common in many species of fungi (as one of the regular phases of the life cycle - in basidiomycetes and in some deuteromycetes ) and occurs with anastomoses of hyphae of different mycelia , which leads to the exchange of cytoplasm and nuclei through anastomosis. Such nuclear heterogeneity - heterocariosis - has adaptive value, since in the case of the presence in the cell of nuclei that differ in several pairs of alleles , it leads to heterozygosity, which makes it possible to compensate for the effect of recessive mutations. Heterocariosis also plays an important role in the reproduction of fungi, since in many groups ( zygomycetes , ascomycetes and basidiomycetes ), the sexual process begins with the conjugation of genetically different hyphae. Depending on the characteristics of the hyphae fusion process, zygogamy (in zygomycetes), gametangiogamy (in ascomycetes) and somatogamy in basidiomycetes are distinguished). ^[one]

Heterocaryons can be obtained by artificially fusing plant or animal cells, treating animal or protoplast cells with agents that cause fusion of cytoplasmic membranes and, accordingly, fusion of cytoplasms. Some viruses (for example, Sendai virus ) or surfactants (lysolecithin, polyethylene glycol ) can be used as agents that cause fusion ^[2] .

In the first division, heterocaryons formed from animal cells can form mononuclear cells, while part of the chromosomes of one or both parent cells are randomly lost (the formation of aneuploids ). Thus, the division of cells containing heterocaryons of human and rodent cells is accompanied by the loss of most of the human chromosomes with frequent preservation of the complete set of rodent chromosomes. The cultures of such hybrid cells are characterized by variability of the number of chromosomes within one line, that is, in this case, the line is characterized not by a stable karyotype , but by a modal number of chromosomes - that is, the most frequent number of chromosomes in a line.

The heterocaryons of higher plants formed during the fusion of protoplasts of various species, in addition to the formation of aneuploids, can produce new hybrid nuclei that preserve both sets of chromosomes, that is, form amphipolyploids ^[3] .

Such cells, obtained by fusion of somatic cells and capable of further division, are called somatic hybrids .

1. ↑ Gorlenko, 1976: p. 18-19.
2. ↑ Sek Wen Hui and David A. Stenger. Electrofusion of cells: Hybridoma production by electrofusion and polyethylene glycol. Methods in Enzymology , Volume 220, 1993, Pages 212-227
3. ↑ Davey MR, Anthony P, Power JB, Lowe KC. Plant protoplasts: status and biotechnological perspectives. Biotechnol Adv. 2005 Mar; 23 (2): 131-71

• Gorlenko M.V. Department of mushrooms (Mycota). General characteristic // Plant Life. T. 2. Mushrooms / Gorlenko M.V., ed. M .: Education, 1976.P. 15-23.

• Heterocariosis
• Nuclear dualism
• Karyotype
• Ploidy