Title: Developmental Potencies of Explanted Quadrants of Hensen's Node.
Abstract: This article is part of a series of studies designed to test the potencies of the embryonic chick blastoderm, particularly that part of the primitive streak designated as Hensen's node. When this node, in stages prior to the formation of the head-process, is transplanted to the chorio-allantoic membrane of 9-day chicks, the grafts that develop contain organs and tissues that are found in the normal embryo as far back as the mesonephros, including tubules (and glomeruli) from that organ. From these observations previously reported it was concluded that Hensen's node at this stage is essentially totipotent. It was also shown that other parts of the blastoderm have a limited capacity, as indicated by the fact that grafts of the area pellucida anterior to the node, or the primitive streak posterior to it, form generalized structures only, such as gut, cartilage, muscle and skin with feather germs. The present experiments were undertaken to ascertain the potencies of different parts of the node. As before, donor blastoderms were used in which there was a definitive primitive streak but no head-process. A median longitudinal cut was made through the primitive streak and a transverse cut through the primitive pit, as a consequence of which the node and area pellucida were divided into 2 equal anterior parts and 2 equal posterior parts. As it was easier to handle large pieces and as regions outside of the node have limited capacities, the area pellucida in the majority of transplants was not excluded. In the remaining experiments only that part of the area pellucida immediately surrounding the node was included with the nodal tissue. As both types of experiment yielded the same results they are considered together.
Publication Year: 1931
Publication Date: 1931-03-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 4
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