Practice question

Commitment progresses through specification followed by determination. A specified cell shows preferential differentiation toward a particular lineage when placed in neutral environment such as in vitro culture lacking instructive signals, indicating initial bias. However, specified state remains labile and reversible upon transplantation into a different embryonic region providing alternative signals. Determined cells, in contrast, retain donor identity even in foreign instructive surroundings due to stabilized transcription factor autoregulation and chromatin modifications. Thus transplantation assays distinguish labile specification, where new environment can overwrite fate, from irreversible determination that resists environmental reprogramming.