title: On periodicity and directionality of somitogenesis.
abstract: It is currently thought that the mechanism underlying somitogenesis is linked to a molecular oscillator, the segmentation clock, and to gradients of signaling molecules within the paraxial mesoderm. Here, we review the current picture of this segmentation clock and gradients, and use this knowledge to critically ask: What is the basis for periodicity and directionality of somitogenesis?
authors.affiliation: Howard Hughes Medical Institute and Stowers Institute for Medical Research, Kansas City, MO 64110, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Aulehla
authors.forename: Olivier
authors.initials: O
authors.lastname: Pourquié
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D019521:Body Patterning / Q000502:physiology*; D047108:Embryonic Development / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D019170:Somites / Q000502:physiology*; D051153:Wnt Proteins / Q000378:metabolism*
chemical_list: D051153:Wnt Proteins