Planarian regeneration between 1960s and 1990s: From skilful baffled ancestors to bold integrative descendants. A personal account

AbstractScientific fields grow by accretion of knowledge brought up by succesive generations of scientists. With the field of planarian regeneration as a general background, here I give a personal account of it from the late 1960s until the late 1990s when new research groups, namely Americans, broke into it. After a short historical summary, I report how I got into regeneration, why I choose planarians, and most especially the finding and description of the current model organism Schmidtea mediterranea. Next, I concentrate on the quantitative cellular approaches to regeneration, growth, and degrowth undertaken in our lab in Barcelona, and the long struggle to set neoblasts as a totipotent/pluripotent heterogeneous population of mitotic and non-mitotic cells for homeostatic somatic cell renewal, reproduction, and blastema formation during regeneration. Finally, the first attempts by several labs to analyze regeneration in molecular terms (RNAs, proteins, mAbs, gene detection, cloning and expression) are also covered.
Along this essay, I am honoured to pay due tribute to our forebears (ancestors) from Morgan and Child to the French School researchers. In spite of being often baffled by planarian ‘tricks’, they struggled hard to find new techniques, new ways, and new ideas to tackle the main problems of regeneration, paving the way to those (descendants) that followed suit.