  We propose a unified mechanism that reproduces the sequence of dynamical
transitions observed during somitogenesis, the process of body segmentation
during embryonic development, that is invariant across all vertebrate species.
This is achieved by combining inter-cellular interactions mediated via
receptor-ligand coupling with global spatial heterogeneity introduced through a
morphogen gradient known to occur along the anteroposterior axis. Our model
reproduces synchronized oscillations in the gene expression in cells at the
anterior of the presomitic mesoderm (PSM) as it grows by adding new cells at
its posterior, followed by traveling waves and subsequent arrest of activity,
with the eventual appearance of somite-like patterns. This framework integrates
a boundary-organized pattern formation mechanism, which uses positional
information provided by a morphogen gradient, with the coupling-mediated
self-organized emergence of collective dynamics, to explain the processes that
lead to segmentation.
