Table of Contents
- 1 What did Hans Spemann discover?
- 2 What is the Mangold Spemann experiment?
- 3 What phenomenon was observed by g Spemann on the example of eye formation?
- 4 What were the findings of Hans Spemann with respect to amphibian development?
- 5 What is the importance of the Spemann organizer in the embryonic development of frogs?
- 6 How does the Spemann organizer work?
- 7 What is the role of cleavage in the early embryo?
- 8 How does a mammalian embryo determine which end is its head and which is its tail?
What did Hans Spemann discover?
The name «organizer centre» or «organizer» was therefore given by him to those parts. For this discovery of the organizer effect in embryonic development, he was awarded the Nobel Prize in 1935. Later Spemann showed that different parts of the organization centre produce different parts of the embryo.
What is the Mangold Spemann experiment?
Spemann himself was a master of transplantation experiments using newt embryos, and Mangold was a gifted student. She performed transplants of the dorsal cells using species with different cell pigmentation, so that transplanted cells could be visually distinguished from host cells by their color.
What was the importance of Spemann’s initial experiment with newt eggs?
The importance of the organizer experiment is the discovery that a part of the mesoderm influences the ectoderm as the ectoderm differentiates into central nervous system tissue.
What phenomenon was observed by g Spemann on the example of eye formation?
The concept of embryological induction, whereby the development of tissues or a structure is affected by closely situated tissues was first clearly demonstrated by Spemann in 1901 in the development of frog embryo eyes.
What were the findings of Hans Spemann with respect to amphibian development?
Spemann concluded from this experiment that early amphibian nuclei were genetically identical and that each cell was capable of giving rise to an entire organism.
How is the Spemann organizer formed?
The organizer is formed in an equatorial sector of the blastula stage amphibian embryo by cells that have responded to two maternal agents: a general mesoendoderm inducer (involving the TFG-beta signaling pathway) and a dorsal modifier (probably involving the Wnt signaling pathway).
What is the importance of the Spemann organizer in the embryonic development of frogs?
The formation of the vertebrate body axis during gastrulation strongly depends on a dorsal signaling centre, the Spemann organizer as it is called in amphibians. This organizer affects embryonic development by self-differentiation, regulation of morphogenesis and secretion of inducing signals.
How does the Spemann organizer work?
The Spemann-Mangold organizer is located in the dorsal blastopore lip, where gastrulation movements originate. Initial organizer cells migrate and localize anteriorly. The organizer cells are subdivided into head, trunk, and tail organizers. The Spemann-Mangold organizer is particularly important in mesoderm induction.
What does the Spemann organizer do?
The Spemann-Mangold organizer is a group of cells that are responsible for the induction of the neural tissues during development in amphibian embryos.
What is the role of cleavage in the early embryo?
In developmental biology, cleavage is the division of cells in the early embryo. Cleavage differs from other forms of cell division in that it increases the number of cells and nuclear mass without increasing the cytoplasmic mass.
How does a mammalian embryo determine which end is its head and which is its tail?
The molecular signals are so-called maternal RNA’s, messages made from the mother’s DNA that will eventually be translated into proteins in the egg cell to let the embryo know that one side is the anterior, or head side, the other the posterior side, and then to know its back, dorsal end, from its front, ventral end.
How is the Spemann organizer distinguished from the other mesodermal cells during induction by the cells of the vegetal region?
Question 10 How is the Spemann organizer distinguished from the other mesodermal cells during induction by the cells of the vegetal region? a) The cells of the Spemann organizer become different as they pass over the dorsal lip of the blastopore during gastrulation.