A correct interpretation of gastrulation is impossible without a knowledge of the position which the presumptive germinal layers occupy in the blastula. This position may be ascertained in various ways. A chart, showing the fate of each part of an early embryo, in particular, a blastula, is called a fate map. In tracing the fate of various parts of the [...]
In this article we will discuss about the concept of gradients in the development of embryo. The Dorsoventral and Anteroposterior Gradients : The phenomenon of regional specificity raises the question of whether the gray crescent does not contain, after all, two or even more different specific substances, responsible for the development of the head and the trunk regions (or the [...]
In this article we will discuss about the process of determining primary organ rudiments of embryos. The activation of genes at the beginning of gastrulation and the resulting synthesis of new kinds of proteins is an important step in development, but in itself it would not be sufficient for initiating the formation of different organs and organ systems of the [...]