Variability- the property of living organisms, including humans, to change their morphofunctional organization, causing a variety of individuals, populations, races, etc.
Any person can be distinguished by a number of signs from another person, even his monozygotic twin. Depending on the nature of I. it is divided into genotypic, or hereditary and phenotypic, or non-hereditary. Genotypic I. is associated with a change in the genotype and therefore is preserved in generations. It is the result of drastic changes in the characteristics — mutations (mutational I.) or the result of new combinations of unchanged genes due to their regrouping in May and the chance of meeting the gametes during fertilization (combinative I.).
When phenotypic I. diversity of organisms occurs without changing the genotype and is not saved in the generations, if there are no conditions in which it arose. Phenotypic I., which occurs under the action of various environmental conditions, including food, lifestyle and other, and expressed in qualities and quantities, deviations from the original form, called.modifying. Genotypic I. is often a source of hereditary diseases.