Velocità di sviluppo della retina di Vertebrati ed aspetti della cromatina nei suoi neuroni

Abstract

Summary The comparative examination of the nuclei of the retinal nerve cells in some Vertebrates has shown that the size-ratio of the retinal nerve cells is different in the various Vertebrates. The beterochromatic network fills the nuclear sap in the Vertebrates whose retina becomes quickly differentiated (Anamniota), on the contrary the network sticks to the nuclear membrane and to the nucleolus (nucleolus-associated chromatin)in the Vertebrates whose retina gets slowly differentiated (Amniota); in the Amniota some heterochromatic structures remain between the nuclear membrane and nucleolus only in the ganglion cells, which develop early and quickly. These results support my previous suggestion that the developmental speed of the nerve cell affects the arrangement of its heterochromatic structures.