title: Developmental dynamics of occipital and cervical somites.
abstract: Development of somites leading to somite compartments, sclerotome, dermomyotome and myotome, has been intensely investigated. Most knowledge on somite development, including the commonly used somite maturation stages, is based on data from somites at thoracic and lumbar levels. Potential regional differences in somite maturation dynamics have been indicated by a number of studies, but have not yet been comprehensively examined. Here, we present an overview on the developmental dynamics of somites at occipital and cervical levels in the chicken embryo. We show that in these regions, the onset of sclerotomal and myotomal compartment formation is later than at thoracolumbar levels, and is initiated simultaneously in multiple somites, which is in contrast to the serial cranial- to- caudal progression of somite maturation in the trunk. Our data suggest a variant spatiotemporal regulation of somite development in occipitocervical somites.
authors.affiliation: Department of Molecular Embryology, Institute of Anatomy, University of Freiburg, Freiburg, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Maschner
authors.affiliation: Institute of Anatomy II, University of Cologne, Cologne, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Krück
authors.affiliation: Institute of Anatomy II, University of Cologne, Cologne, Germany.
authors.forename: Margarethe
authors.initials: M
authors.lastname: Draga
authors.affiliation: Institute of Anatomy II, University of Cologne, Cologne, Germany.
authors.forename: Felicitas
authors.initials: F
authors.lastname: Pröls
authors.affiliation: Institute of Anatomy II, University of Cologne, Cologne, Germany. martin.scaal@uk-koeln.de.|Department of Molecular Embryology, Institute of Anatomy, University of Freiburg, Freiburg, Germany. martin.scaal@uk-koeln.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Scaal
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002574:Cervical Vertebrae; D002642:Chick Embryo; D047108:Embryonic Development; D017403:In Situ Hybridization; D009777:Occipital Bone; D019170:Somites / Q000196:embryology*
keywords: 
  MyoD
  ; 
  Pax1
  ; cervical; chicken embryo; myotome; occipital; sclerotome; somite