118 The Nature of Biological Diversity 



ration of genes and cytoplasm. During development, genes and cyto- 

 plasm interact with one another to produce new patterns of active 

 genes, which lead to the synthesis of new varieties of proteins and 

 thus to an altered cytoplasm. This cyclic interaction makes possihle 

 progressive cell differentiation through the synthesis of new proteins 

 and constitutes the foundation of all emhryonic development. 



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