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 [...]
The cytoplasm of the egg, and particularly its cortex, starts the chain of reactions which eventually leads to the differentiation of parts of the embryo, it should not be assumed that the structure of the future embryo is rigidly determined by local differences in the cytoplasm of the egg. The local peculiarities of the egg cytoplasm are only some of [...]
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 [...]