Distribution of two individual DNA fragments with lengths of 10.4 and 1.4 kb over various cell compartments of MCF-7 cell culture depending on the time they were present in the culture medium (electrophoresis under native conditions, logarithmic stage of cell culture growth, absence of salmon sperm DNA as competitor, and blunt ends). Agarose blocks stained with ethidium bromide are shown rightward; X-ray patterns of the same blocks after drying, leftward. Numbers above the blocks indicate the time of cell culture incubation with α32P-labeled fragments; numbers to the left and right of the blocks, markers of molecular weight (Kb); V, number of experiment. Degradation of the initial DNA fragments is observed already in the culture medium. Similar to human DNA, the heterologous DNA enters general cell compartments – cytoplasm and nucleus.