In this article we will discuss about the involvement of parental genes in the development of control of embryos. Apart from the foregoing data, which characterize the activity of the nuclear DNA in general terms, there are many indirect indications that nuclear genetic factors (the genes), after having been dormant throughout the period of cleavage, begin to manifest themselves during [...]
In this article we will discuss about the process of gastrulation in amphioxus and amphibians. Gastrulation in Amphioxus: In Amphioxus, there are differences in the various regions of the egg cytoplasm which permitted Conklin (1932) to trace these regions into the later stages of development and thus to reconstruct a fate map, at least in rough outlines. At the beginning [...]
Immigration of mesodermal cells from the primitive streak in amniotes and migration of mesenchyme cells in sea urchin gastrulation can be regarded as examples of an important step in morphogenesis – the creation of mesenchyme-type tissues, which are a new structural element of an animal's body. The mesenchyme cells are not linked together, as are epithelial cells. They are free [...]