HETEROKARYOSIS IN FUNGI
HETEROKARYOSIS IN FUNGI ❖ Heterokaryosis is the main source of variation in the anamorphic (imperfect) fungi, which lack sexual reproduction. The term Heterokaryosis was proposed by Hansen and Smith in 1932, who reported it for the first time in Botrytis cinerea . ❖ The presence of genetically-different nuclei in an individual is called heterokaryosis, and the organism heterokaryon. ❖ Essentially, a heterokaryon possesses two sets of chromosomes, just like a diploid organism, but instead of being contained in a single nucleus, the two sets of chromosomes lie in separate nuclei, sharing the same cytoplasm. ❖ Heterokaryons show dominance and, thus, resemble diploids in many respects. Heterokaryosis is a major factor in natural variability and sexuality. ❖ The heterokaryotic condition can arise in a fungus by three methods, viz., (1) Mutation, (2) Anastomosis i.e., fusion between genetically-different hyphae, and (3) Diplodization-fusion between haploid nuclei to form...
