In this study, we have examined the effect of 5-bromo-2'-deoxyuridine incorporated into DNA of Drosophila nerve cells after incubation of larvae in the analog-containing medium on the duration of lifespan and behavior (photoactivity) of adult flies. 5-Bromo-2'-deoxyuridine incorporated into DNA decreases the lifespan of adult animals. In contrast to the control, the curves describing the probability of death become bimodal at higher doses of the analog (above 35 (g/ml). As the dose of 5-bromo-2'-deoxyuridine decreases, photoactivity of the flies diminishes, and the distribution into fractions with different activity becomes broader. The data obtained provide evidence that the modification of DNA with 5-bromo-2'-deoxyuridine drastically changes the expression of tissue-specific genes in nerve ganglia of Drosophila and at the same time diminishes the duration of insects lifespan. These observations suggest that genome of the nerve cells appears to be a probable initial substrate of Drosophila aging.