ORIGINS AND SIGNIFICANCE OF GENETIC AND EPIGENETIC INSTABILITY IN MYCELIAL SYSTEMS

Fungal mycelia can alter their organizational pattern in such ways as to produce alternative phenotypes. The latter allow mycelia to explore for, assimilate, conserve, and redistribute resources in spatially an d temporally heterogeneous niches. It is suggested that mycelia produc e alternative phenotypes by operating as nonlinear (feedback regulated ), hydrodynamic systems with indefinitely expandable (indeterminate) b oundaries. As such, mycelia can vary the resistances of hyphal envelop es to deformation and passage of molecules, and of hyphal interiors to displacement of contents, in accord with fortuitous local circumstanc es. Within the mycelial protoplasm are populations of nuclei and mitoc hondria. If disparate in genetic content or expression, these organell es can form diverse and unstable relationships that both influence and are influenced by metabolic processes affecting the hydraulic resista nces of hyphae. Some of these processes may be autocatalytic, involvin g the generation, association and dissociation of free radicals and re active oxygen species. Once initiated, such processes are beyond immed iate genetic control. Fungal mycelia therefore epitomize the complex i nterplays between adaptive (genetic) and nonadaptive (organizational) processes that regulate the short term versatility and long term evolu tionary divergence of indeterminate systems.