Hormesis–An Exciting Field in Genetic Toxicology and Evolutionary Biology

The term ‘hormesis’ describes the beneficial effects at low concentrations/doses of substances/agents which at higher doses are toxic/lethal. Hormesis means ‘to excite in small amounts’: Greek ‘Hormoligosis’. The effects seem to be largely physiological in nature at low concentrations/ doses; at higher doses the agents cause genotoxicity expressed as chromosomal aberrations, mutations, cancer and lethality. However, toxic effects noted at high doses cannot be anticipated by extrapolation of dosage. Agathokleous et al. (Environ. Res., 2018, 165, 274–278) observe that hormesis rewrites the history of toxicology. Hormesis was invariably encountered by genetic toxicologists working with physical and chemical genotoxic agents since 1974 when research on environmental mutagens gained momentum in several scientifically advanced countries including India. As early as 1975, scientists at the Bhabha Atomic Research Centre (BARC), Mumbai not only pioneered research in environmental mutagenesis, but also, supported initiation of research in this field in several universities. Many scientists recorded that several genotoxins at low doses/concentrations reduced the spontaneous level of adverse effects.