In adult planarians, the replacement of cells lost to physiological turnover or damage is sustained through the proliferation and differentiation selleck of stem cells known as neoblasts. Neoblast lineage relationships along with the molecular improvements that get place throughout differentiation into the appropriate cell sorts are poorly understood. Right here we report the identification and characterization of the cohort of genes particularly expressed in neoblasts and their descendants. We find that genes with severely downregulatedc-Jun N-terminal kinases (JNKs) expression after irradiation molecularly define at the least three discrete subpopulations of cells. Simultaneous BrdU labeling and in situ hybridization experiments in intact and regenerating animals indicate that these cell subpopulations are related by lineage. Our data demonstrate not only the ability to measure and review the in vivo population dynamics of grownup stem cells throughout tissue homeostasis and regeneration, but additionally the utility of scientific studies in planarians to broadly inform stem cell biology in adult organisms.