| Autor: |
ARNOLD, JOHN M., WILLIAMS-ARNOLD, LOIS D. |
| Zdroj: |
American Zoologist; Jul1976, Vol. 16 Issue 3, p421-446, 26p |
| Abstrakt: |
In many spiralian embryos it has been possible to demonstrate that embryonic development is partially controlled by cytoplasmic factors located at or in the surface of the fertilized egg and cleaving embryo. In the embryo of the squid , a pattern of developmental information can be demonstrated to exist at the surface, or the egg cortex, of the fertilized but uncleaved embryo. The informational pattern apparently is released or activated during the time of the cytoplasmic streaming which forms the blastodisc. Eventually this developmental informational pattern is imposed upon the blastoderm cells that come to cover organ-specific regions of the yolk syncytium which was derived from the egg cortex. Ultrastructural studies demonstrate many intercellular connections between the yolk syncytium and the blastoderm and between the cells of the blastoderm itself. During oogenesis there are regional differences in the follicular syncytium which suggests that the pattern of developmental information may arise in the ovary and be retained in a latent state until triggered by fertilization. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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