This allowed the blastoderm
to float upward and take a position over the yolk sac just beneath the shell.
The gastrulation stage ends when the blastoderm
completely covers the yolk, characterizing the 100% epiboly stage, which is marked by the presence of primary germ layers (endoderm, mesoderm and ectoderm) and the embryonic axis, giving rise to the subsequent stage characterized by organogenesis (Wolpert et al.
One had arrested growth at early vascularised blastoderm
about the time the blastoderm
is formed); 8 d old [i.
The egg which were incubated for 11 h our showed distract evidences of cleavage, especially superficial cleavage, resulting in the formation of uniform monocellular blastoderm
At midblastula, cells of the blastoderm
become mobile and spread over the yolk in the process known as epiboly.
Eggs on which the blastoderm
was visible, were recognized as recently fertilized.
Segmental organization of the head in the embryo of Drosophila melanogaster: A blastoderm
fate map of the cuticular structures of the larval head.
of a fertilized egg and the point at which embryonic development starts in the making of a chick.
The model to be used here refers to the expression pattern of transcription factor genes only in one developmental stage and only in one cell or a body region that shares an expression pattern, such as, for example, a set of nuclei in a part of a Drosophila blastoderm
expressing a specific subset of segmentation genes (Ingham 1988).
Then eggs were placed in the racks with their blunt ends above and pointed ends below, and left in this position for 5 to 15 minutes to let the blastoderm
to rotate and come to lie above at the blunt end.
The ostrich (Struthio camelus) blastoderm
and embryo development following storage of eggs at various temperatures.
Gradually the blastoderm
formed into several layers due to further cell division which is called blastodisc.