Regulation of Structural Sperm Protein Synthesis by Y Chromosomal Loci

Cellular differentiation is usually controlled by regulatory processes at the genomic level. In principle, two aspects of such regulatory events might be considered. External signals can determine the response of the genome of a cell to distinct environmental conditions. An example of this type has been given by Pongs (this volume). Ecdysone interacts with distinct genetic loci leading to metabolic changes in the cells which are related to molting or puparium formation. Alternatively, regulatory genes may govern the activities of other genes during development. Such a concept has been developed by Garcia-Bellido [1] who postulated the existence of “selector genes” which determine certain differentiation pathways. Although genetics has provided evidence on the existence of such regulatory genes, their exact nature is still unclear.