In this article we will discuss about the selective affinities of cells as a determining factor in cellular rearrangements of an embryo. We may ask what is the nature of the forces which control the rearrangement of cells resulting from morphogenetic movements in gastrulation and also in other morphogenetic processes; we may ask whether the new positions of the cells [...]
In this article we will discuss about the gene activity during gastrulation period of embryos. Fragments of sea urchin eggs not containing the nucleus may be treated with agents who cause parthenogenetic activation of the egg (viz., hypertonic seawater). It has been found that the non-nucleated fragments begin to cleave and may reach the morula stage. The animals (embryos), however, [...]
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 [...]