How Does the Embryo Take Form and Differentiate to Become an Organised Organism?”

1247 Words 5 Pages
Throughout this discovery process there have been many questions that have guided the scientific community towards finding answers. One of the earlier questions was “how does the embryo take form and differentiate to become an organised organism?”
This question began to be answered in 1924, when H Spermann and H mangold published a paper describing their experimentation with newt embryos. They discovered that by taking the dorsal lip and transferring it to the ventral side of a new embryo; it would form a new embryonic axis by instructing surrounding cells to undergo neutralisation and dorsalisation alongside a pre-existing embryo (Spermann & Mangold, 1924). The reason this had such large implications was because it proved that the portion they had removed was the organiser of the embryo, dictating each cells fate and ensuring a proper axis was formed. However, soon after this discovery, the next question became “how does the organiser decide cell fate and create embryonic axis?”
In 1995 Levin and Johnson et al began studying the embryo of chicks, with particular interest in the genes surrounding the node, including Sonic Hedgehog. Through the use of in situ hybridisation, fluorescent cell labelling, activin bead implants between the endoderm and ectoderm, followed by the implantation of either an SHH-expressing retrovirus or a control cell pellet that acted as the control (Levin & Johnson et al, 1995). This led to the discovery of nodal in the chick embryo, which Levin…