We have recently reported that DNA and chromatin fragments derived from apoptotic cells that circulate in blood of human beings can readily enter into somatic cells of mice in vitro and in vivo, evoke a DNA damage repair response and integrate themselves into their genomes. However, these findings are at odds with established knowledge on two counts: first, DNA is not known to spontaneously enter into cells, and second, DNA is not known to have any intrinsic biological properties.