Since many of our working concepts and much of our present understanding of mammalian chromosomes stem from earlier studies on lower organisms, participants in the symposium have endeavored to include the pertinent relationships compiled for the more classical species. The reader must be warned that no attempt has been made to abbreviate or simplify terms regarding the structural and functional aspects of the mammalian chromosome, even though current descriptions have led many of us to the brink of making such proposals. I trust the reader will keep in mind that the perplexing dynamics embodied in the mitotic and meiotic chromosomes defy one's efforts truly to improve upon the working terminology employed at this time. However, at the present rate of progress, this area will experience drastic lexicographic revisions very shortly. It is said that one looks into a microscope, his eyes adjust to a focal distance of infinite length.
Perception is restricted to a flattened image, lacking three dimensional depth of field.
Perhaps this deletion is responsible for the hypnotic spells one experiences while viewing the dense and static metaphase chromosome. Once the spell is broken, the viewer may find himself reliving the patience, curiosity, and imagination of earlier investigators in their attempts to relate functional and structural aspects of the chromosomes to visual differences in the staining capacity of distinct segments. This may be regarded as the first attempt to associate structural with functional aspects of the chromosome. Because of its rigid oversimplification, usage of these terms was soon challenged by Darlington and others during the '30s. By the mid-40s, Casperrson and his associates proposed that inactivation of genes was due to associated histones, while globulins were associated with active genes.