 The study demonstrates that a direct, positive autoregulatory loop amplifies and maintains crocs-20 expression in vertebrate hindbrain segmentation using enhancer knockout in mice, and reveals the molecular mechanisms underlying this feedback loop through quantitative data collected in zebrafish and biophysical modeling. The study shows that the stochasticity of the activation process leads to a graded input-output response until saturation is reached, another duration and strength of the input signal controls the size of hindbrain segments by modulating the distribution between two cell fates. Additionally, the progressive extinction of crocs-20 expression involves destabilization of the loop by repressor molecules, which have general significance for cell-type specification and tissue patterning. This article was authored by Yassine Expertuture, Eugen Reingrubber, Charlotte Labellette, and others.