The development of cell senescence.

Cellular senescence was traditionally considered a stress response that protected the organism by limiting the proliferation of damaged and unwanted cells. However, the recent identification of developmentally-programmed cellular senescence during embryo development has changed our view of the process. There are now a number of examples of developmental senescence in evolutionary distant organisms ranging from mammals to fish, showing senescence at various sites during specific time windows of development. Developmental senescence shares many features with stress-induced senescence but also present some specific characteristics. The different examples of developmental senescence provide evidence of the diverse functions contributed by senescence and represent an opportunity to learn more about this process. Also, the existence of senescence during embryogenesis opens the possibility of identifying human developmental syndromes caused by alterations in this response. Studying in more detail this process will expand our understanding of cellular senescence and could offer new insights into the cause of human pathologies.