Hereditary mutations arise from errors during the replication process of germline cells that are not corrected by DNA repair mechanisms. Mutations of endogenous origin are a reflection of the intrinsic deficiencies of cellular molecular systems and oxidative, alkylation, or methylation damage to nitrogenous bases, while exogenous mutations are the result of environmental factors such as various chemical agents, ionizing or non-ionizing radiation. The development of whole-genome sequencing technology and bioinformatics tools for data processing has enabled the detection of the presence and relative prevalence of specific mutations at the level of the entire genome. Mutation spectra are characteristic of different species and their populations. Hereditary genetic elements that influence the fidelity of replication and DNA repair mechanisms are mutators and antimutators. These are modifiers of the mutation rate, causing an increased or decreased mutation rate within an individual. During favorable environmental conditions, selective pressure acts to eliminate the mutator phenotype from the population, however, individuals with an increased mutation rate have a greater chance of developing adaptive mutations during stressful environmental conditions, thus propagating the mutator phenotype. The gradual reduction of the mutation rate across generations is limited by the barrier of genetic drift, after which stochastic processes dominate natural selection. Somatic mutations are not hereditary, however, they have a significant impact on the characteristics of an organism's life. An inversely proportional correlation between the somatic mutation rate and the lifespan of different species has been established.