In this article we will discuss about the manifestation of maternal genes during the early stages of development. Evidence has been presented that (1) the differences between the various parts of the embryo are not due to differences in their nuclei but to differences in the cytoplasm. From this it may be inferred that (2) the nuclei of the cleavage [...]
Distribution of visible materials in the egg and in the embryo during cleavage is, however, not always of crucial importance for the localization of parts in the developing embryo. Some substances and cellular inclusions may be displaced without disturbing the normal segregation of the embryo into its subordinate parts. This displacement can most conveniently be accomplished by centrifugation of the [...]
In this article we will discuss about:- 1. Definition of Cleavage 2. Chemical Changes during Cleavage 3. Patterns 4. Nuclei of Cleavage Cells 5. Morula and Blastula. Definition of Cleavage: One of the peculiarities of sexual reproduction in animals is that the complex multicellular body of the offspring originates from a single cell—the fertilized egg. It is necessary, therefore, that [...]