text: In the field of cell biology, the method of partial cloning (PCL) converts a fully differentiated old somatic cell into a partially reprogrammed  young cell that retains all the specialised functions of the differentiated old cell but is simply younger.  The method of PCL reverses characteristics associated with old cells.  For example, old, senescent, cells rejuvenated by PCL are free of highly condensed senescence-associated heterochromatin foci (SAHF) and re-acquire the proliferation potential of young cells.  The method of PCL thus rejuvenates old cells without de-differentiation and passage through an embryonic, pluripotent, stage.