Affiliations: Graduate Program in Genetics Department of Molecular
Genetics and Microbiology State University of New York at Stony Brook Stony
Brook, NY 11794-5222, USA. E-mail: [email protected] | Schumacher College The Old Postern, Dartington Totnes,
Devon TQ9 6EA, UK
Note: [] Corresponding author
Abstract: Kinetic modeling of developmental dynamics requires detailed
knowledge about genetic and metabolic networks that underlie developmental
processes. However, such knowledge is not available for a vast majority of
developmental processes. Here, we present an coarse-grained, phenomenological
model of periodic pattern formation in multicellular organisms based on
cellular oscillators (CO) that can be applied to systems for which little or no
molecular data is available. An oscillatory process within cells serves as a
developmental clock whose period is tightly regulated by cell-autonomous and
non-autonomous mechanisms. A spatial pattern is generated as a result of an
initial temporal ordering of the cell oscillators freezing into spatial order
as the clocks slow down and stop at different times or phases in their cycles.
When applied to vertebrate somitogenesis, the CO model can reproduce the
dynamics of periodic gene expression patterns observed in the presomitic
mesoderm. Different somite lengths can be generated by altering the period of
the oscillation. There is evidence that a CO-type mechanism might also underlie
segment formation in certain invertebrates, such as annelids and short germ
insects. This suggests that the dynamical principles of sequential segmentation
might be equivalent throughout the animal kingdom although most of the genes
involved in segment determination differ between distant phyla.
Keywords: segmentation, somitogenesis, short-germ band insects, cellular oscillators , phenomenological modeling, coarse-grained modeling, evolution of development, developmental dynamics
