Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 8: Developmental Processes
BP 8.6: Vortrag
Dienstag, 24. März 2009, 11:30–11:45, HÜL 186
Slowing down of genetic oscillations in vertebrate segmentation — •Saul Ares1, Luis G. Morelli1, Andrew C. Oates2, and Frank Julicher1 — 1Max Planck Institute for the Physics of Complex Systems — 2Max Planck Institute of Molecular Cell Biology and Genetics
The subdivision of the vertebrate body axis in a segmented pattern is driven by genetic oscillations in the unsegmented tissue called the Presomitic Mesoderm (PSM). These oscillations form waves of gene expression that start at the posterior of the PSM and move anteriorly to finally stop at an arrest front. In situ snapshots of the PSM display a gene expression pattern of several stripes which are thiner at the anterior. Recently, Gomez et al. [Nature, 454, 335-339 (2008)] have analyzed experimentally embryos of snake, mouse, chick and zebrafish, measuring the sizes of their PSM and the different number of stripes of cyclic gene expression in each species (from 1 in mouse or chick to up to 9 in snake).
In this contribution we present a Delayed Coupling Theory of vertebrate segmentation that treats the cellular oscillators as phase oscillators coupled with a time delay. Using this theory we analyze the data from Gomez et al. and show for the first time that the way in which oscillators slow down across the PSM is different and characteristic of each species. Together with the PSM size and the collective period of the oscillations, the way in which the oscillator slow down establishes the gene expression pattern setting the number and size of the stripes of cyclic gene expression in the PSM.