Delayed coupling theory of vertebrate segmentation

Rhythmic and sequential subdivision of the elongating vertebrate embryonic body
axis into morphological somites is controlled by an oscillating multicellular
genetic network termed the segmentation clock. This clock operates in the
presomitic mesoderm (PSM), generating dynamic stripe patterns of oscillatory
gene-expression across the field of PSM cells. How these spatial patterns, the
clock\'s collective period, and the underlying cellular-level interactions are
related is not understood. In this talk we introduce a delayed coupling theory
that represents the PSM as an array of phase oscillators, combining four key
elements: a frequency profile of oscillators slowing across the PSM; coupling
between neighboring oscillators; delay in coupling; and a moving boundary
describing embryonic axis elongation. This theory combines several
spatiotemporal aspects and predicts that the segmentation clock\'s collective
period depends on delayed coupling, a prediction experimentally confirmed and
that will be more carefully explained in Tuesday\'s seminar by Andrew Oates.