Open AccessPhysico-chemical experiments on the amphibian organizer
Author(s) -
Joseph Needham,
C. H. Waddington,
Dorothy M. Needham
Publication year - 1934
Publication title -
proceedings of the royal society of london. series b, containing papers of a biological character
Language(s) - English
Resource type - Journals
eISSN - 2053-9185
pISSN - 0950-1193
DOI - 10.1098/rspb.1934.0014
Subject(s) - notochord , gastrulation , biology , ectoderm , endoderm , neural tube , anatomy , neural plate , embryo , embryogenesis , embryology , amphibian , histogenesis , microbiology and biotechnology , embryonic stem cell , paleontology , genetics , immunohistochemistry , gene , immunology
A turning-point of the highest importance in the history of embryology was reached when in the spring of 1924 H. Spemann and H. Mangold obtained the first induction by the organizer of an amphibian egg. Th dorsal lip of the blastopore of an embryo ofTriton cristatus was transplanted into the indifferent ectoderm of an embryo ofTriton taeniatus at the same stage of development,i. e ., the early gastrula. There it did not behave as presumptive medullary plate or epidermis would have done, but on the contrary asserted itself in its new environment by inducing the formation of a new embryonic axis. Two embryos were thus produced on an egg which normally would have formed only one, for the induced structures included neural tube, notochord, auditory vesicles, mesoblastic somites, and Wolffian ducts. Spemann (1921) gave the name "organizer" to cells capable of inducing the formation of newAnlagen , and that of "orgaization-centre" (1918) to the region where such cells are situated during normal development. For this fundamental discovery two main achievements of preparatory investigation had been required. In the first place it had been essential to discover the normal fate of every portion of the amphibian egg and the normal direction of the cell-streams before, during, and after gastrulation. This was accomplished by Vogt (1923, 1925) who stained patches of ectoderm with various dyes and followed the paths taken by the coloured pieces.