Anatomy and Embryology

, Volume 207, Issue 4–5, pp 263–272 | Cite as

Notochord segmentation may lay down the pathway for the development of the vertebral bodies in the Atlantic salmon

  • Sindre GrotmolEmail author
  • Harald Kryvi
  • Kari Nordvik
  • Geir K. Totland
Original Article


This study indicates that the development of the vertebrae in the Atlantic salmon requires the orchestration of two sources of metameric patterning, derived from the notochord and the somite rows, respectively. Before segmentation of the salmon notochord, chordoblasts exhibit a well-defined cell axis that is uniformly aligned with the cranio-caudal axis. The morphology of these cells is characterised by a foot-like basal projection that rests on the notochordal sheath. Notochordal segments are initially formed within the chordoblast layer by metameric change in the axial orientation of groups of chordoblasts. This process results in the formation of circular bands of chordoblasts, with feet perpendicular to the cranio-caudal axis, the original chordoblast orientation. Each vertebra is defined by two such chordoblast bands, at the cranial and caudal borders, respectively. Formation of the chordoblast segments closely precedes formation of the chordacentra, which form as calcified rings within the adjacent notochordal sheath. Sclerotomal osteoblasts then differentiate on the surface of the chordacentra, using them as foundations for further vertebral growth. Thus, the morphogenesis of the rudiments of the vertebral bodies is initiated by a generation of segments within the chordoblast layer. This dual segmentation model for salmon, in which the segmental patterns of the neural and haemal arches are somite-derived, while the vertebral segments seem to be notochord-derived, contrasts with current models for avians and mammals.


Notochord Segmentation Vertebral body Ontogenesis Chordacentrum Teleost fish Atlantic salmon 



We gratefully acknowledge the expert help of Marine Harvest Norway AS (Tveitevågen) in rearing the eggs and larvae of the Atlantic salmon. We thank Nina Ellingsen and Teresa Cieplinska for excellent technical assistance. The Research Council of Norway funded this project.


  1. Aoyama H, Asamoto K (2000) The developmental fate of rostral/caudal half of a somite for vertebra and rib formation: experimental confirmation of the resegmentation theory using chick-quail chimeras. Mech Dev 99:71–82CrossRefGoogle Scholar
  2. Arratia G, Schultze H-P, Casciotta J (2001) Vertebral column and associated elements in dipnoans and comparison with other fishes: development of homology. J Morph 250:101–172CrossRefPubMedGoogle Scholar
  3. Brand-Saberi B, Christ B (2000) Evolution and development of distinct cell lineages derived from somites. Curr Top Dev Biol 48:1–42PubMedGoogle Scholar
  4. Christ B, Huang R, Wilting J (2000) The development of the avian vertebral column. Anat Embryol 202:179–194CrossRefPubMedGoogle Scholar
  5. Fleming A, Keynes RJ, Tannahill D (2001) The role of the notochord in vertebral column formation. J Anat 199:177–180PubMedGoogle Scholar
  6. François Y (1966) Structure et développement de la vertèbre de Salmo et des téléostéens. Arch Zool Exp Gén 107:287–328Google Scholar
  7. Goodrich ES (1930) Studies on the structure and development of vertebrates. Macmillan, LondonGoogle Scholar
  8. Koehl MAR, Quillin KJ, Pell CA (2000) Mechanical design of fiber-wound hydraulic skeletons: The stiffening and straightening of embryonic notochords. Amer Zool 40:28–41Google Scholar
  9. Maroto M, Pourquié O (2001) A molecular clock involved in somite segmentation. Curr Top Dev Biol 51:221–248PubMedGoogle Scholar
  10. Morin-Kensicki EM, Melancon E, Eisen JS (2002) Segmental relationship between somites and vertebral column in zebrafish. Development 129:3851–3860PubMedGoogle Scholar
  11. Philpott DE (1966) A rapid method for staining plastic-embedded tissues for light microscope. Sci Instrum 11:11–12Google Scholar
  12. Pourquié O (2002) Vertebrate segmentation: lunatic transcriptional regulation. Curr Biol 12:699–701CrossRefGoogle Scholar
  13. Remak R (1850) Untersuchungen über die Entwicklung der Wirbeltiere. Reimer, BerlinGoogle Scholar
  14. Saga Y, Takeda H (2001) The making of the somite: molecular events in vertebrate segmentation. Nat Rev Genet 2:835–845CrossRefPubMedGoogle Scholar
  15. Stickney HL, Barresi MJF, Devoto SH (2000) Somite development in zebrafish. Dev Dyn 219:287–303CrossRefPubMedGoogle Scholar
  16. Stockdale FE, Nikovits W, Christ B (2000) Molecular and cellular biology of avian somite development. Dev Dyn 219:304–321CrossRefPubMedGoogle Scholar
  17. Taylor WR, van Dyke GC (1985) Revised procedures for staining and clearing small fishes and other vertebrates for bone and cartilage study. Cybium 9:107–119Google Scholar
  18. van Eeden FJ, Granato M, Schach U, Brand M, Furutani Seiki M, Haffter P, Hammerschmidt M, Heisenberg CP, Jiang YJ, Kane DA et al. (1996) Mutations affecting somite formation and patterning in the zebrafish, Danio rerio. Development 123:153–164PubMedGoogle Scholar

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • Sindre Grotmol
    • 1
    Email author
  • Harald Kryvi
    • 1
  • Kari Nordvik
    • 1
  • Geir K. Totland
    • 1
  1. 1.Department of ZoologyUniversity of BergenBergenNorway

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