Nuclear genetic material as an initial substrate of aging in animals

General properties of aging in animals are considered on the basis of the l iterature evidence and the results obtained by the authors of this paper. T he existence of a specific aging mechanism is inferred. The operation of th is mechanism is controlled not only by genes but also by particular noncodi ng genomic sequences with variable structure. The beginning of senescence i n animals is determined by DNA lesions located in neural cells and probably in a minor genomic fraction. The authors refute the narrow concept of agin g as a mechanism increasing the probability of death. Mortality as a contin uous process occurring with the probability of 100 percent is an integral a ttribute of living organisms on the Earth.