Functional-Genetic Mosaicism in Cell Population

Abstract

One of the important results of nuclear-cytoplasmic interactions is the realization of the complex processes which caused cell determination—the main event in ontogenesis. In discussing cell determination in his classic work in experimental embryology, Spemann (1938) wrote, “Usually we follow the definition given many years ago by K. Gaider, according to whom determination is the causal conditionally of the future fate of the embryonic parts. This causal conditionality is occurring or has occurred”. Moreover, Filatov (1934) defined the process of determination as “the effect of some parts of the developing organism on other parts which, as a result, go through part of their development under specific conditions.” Ha- dorn (1965) characterized determination as a “process, the result of which allows a competent cell to choose one from many developmental pathways”.