Author

Richard Harland

Published on SDB CoRe: Feb 15 2013

Early Embryogenesis: Cleavage; Blastula
Morphogenic Movements: Gastrulation
Embryonic Patterning: Axis Formation
Morphogenesis: Cell Movements
Organism: Ctenophore
Stage of Development: Embryo

Object Description

Ctenophores or comb jellies are marine invertebrates that develop rapidly from a 1-cell embryo to a swimming larva in less than 24 hours.  This movie shows 4.5 hours of development of several ctenophore (Mnemiopsis leidyi) embryos.  At the beginning of the movie (00:00), the bottom center embryo is beginning its first cleavage (lateral view).  Ctenophore cleavages are unipolar—they move like a zipper from one side of the cell to the other.  The first cleavage begins at the oral pole zipping along the sagittal plane of the embryo.  The second cleavage (00:01) runs through the tentacular plane (where the tentacles will form) producing a 4-cell embryo.  Unequal cell divisions after the 8-cell stage (00:02) produce micromeres on the aboral side of the embryo (00:04-00:06). Epiboly signifies the beginning of gastrulation when the micromeres migrate over the macromeres (00:07). The movie ends at the late gastrula stage.  This movie was made at the 2006 Marine Biological Laboratory Embryology Course with embryos provided by Mark Q. Martindale.

References

Martindale, M.Q., Henry, J.Q. Reassessing embryogenesis in the Ctenophora: the inductive role of e1 micromeres in organizing ctene row formation in the ‘mosaic’ embryo, Mnemiopsis leidyi. Development, 1997, 124:1999-2006.

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