Nuclear Differentiation and Functional Morphology of Chromosomes

Abstract

The classical concept of cellular differentiation as formulated by Boveri (1904) more than 50 years ago, may be stated in modern terms as follows: 1) All cells of an individual or, in Protozoa of a clone, obtain two or some other number of complete sets of chromosomes and genes by means of mitosis, a process especially evolved to this end. 2) Differentiation is primarily cytoplasmic. It does not normally involve irreversible, that is, mutational changes of chromosome or gene structure and number (other than polyploidy), but may cause reversible changes in gene activity.