ISSN: 2641-9165
Authors: Otsuka J*
The recent genome sequencing of multicellular diploid eukaryotes reveals an enlarged repertoire of protein genes for signal transmission but it is still difficult to elucidate the network of signal transmission to drive the life cycle of such an eukaryote only from biochemical and genetic studies. In the present paper, a theoretical study is carried out for the cell differentiation, the formation of stem cells and the growth from a child to the adult in the higher animal. With the intercellular and intracellular signal transmission in mind, the cell differentiation is theoretically derived from the process by the transition of proliferated cells from proliferation mode to differentiation mode and by both the long-range interaction between distinctive types of cells and the short-range interaction between the same types of cells. As the hierarchy of cell differentiation is advanced, the original types of self-reproducible cells are replaced by the self-reproducible cells returned from the cells differentiated already. The latter type of self-reproducible cells are marked with the signal specific to the preceding differentiation and become the stem cells for the next stage of cell differentiation. This situation is realized under the condition that the differentiation of cells occurs immediately after their proliferation in the development. The presence of stem cells in the respective lineages of differentiated cells strongly suggests another signal transmission for the growth of a child to a definite size of adult that the proliferation of stem cells in one lineage is activated by the signal from the differentiated cells in the other lineage(s) and is suppressed by the signal from the differentiated cells in its own lineage. This style of signal transmission also explains the metamorphosis and maturation of germ cells in higher animals.
Keywords: Development; Growth Curve; Hormones; Metamorphosis; Signal Transmission
