One of the classical problems of embryology has been that of the origin of the primordial germ cells.Weismann (1885)proposed that a specific region of cytoplasm, the so-calledgerm plasm,was set aside in the fertilizedeggand that this was the forerunner of the entirelineageof thegerm line. Th...
Morgan also rejected Weismann’s theory and he did experiments on tadpoles which gave him two ideas on his book on regeneration: First, regeneration is a natural process related to normal development and differentiation. Second, cell fate is not predetermined by heredity or by the cell’s ...
The first report of cell death was by Vogt in 1842, which was remarkably soon after the establishment of the cell theory by Schleiden and Schwann between 1838 and 1842. Initial studies on cell death, including that of Vogt, focused on its occurrence in metamorphosis (Vogt, 1842; Prévost ...
showing that the nucleus of the sperm enters the oocyte and fuses with its nucleus. This was the first time it was suggested that an individual develops from a (single) nucleated cell. This was in contradiction to Ernst Haeckel's theory that the complete phylogeny of a species...
The concept that the germline is distinct from the soma was introduced in the late 19th century by August Weismann[1]. In his Germ Plasm Theory he emphasized the continuity of the germline, which is both totipotent and immortal. The germ plasm, a collection of genetic determinants found in ...
Ingerm-plasm theory …is the essential element of germ cells (eggs and sperm) and is the hereditary material that is passed from generation to generation. Weismann first proposed this theory in 1883; it was later published in his treatiseDas Keimplasma(1892;The Germ-Plasm: A Theory of Heredi...