The study of genetic information carriers—DNA and RNA—depends to a large degree on the possibility of identifying sequences of these materials; that is, determining which sequences are similar or identical, and which are dissimilar. A complete chemical analysis of each molecule would be the most satisfactory method, but such an analysis, although possible, is very laborious, and it needs a [...]
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 [...]