CYTOFLUOROMETRIC EVIDENCE FOR DIFFERENTIAL GENOME ENDOREPLICATION IN THE CLUSTER NEURONS OF LOPHIUS-PISCATORIUS L (OSTEICHTHYES, LOPHIIFORMES)

Quantitative microfluorometric evaluation indicated that, in Lophius p iscatorius, the DNA content of large neurons of a cluster located at t he boundary between the medulla oblongata and the spinal cord varied f rom 4C to more than 5000C. This finding must be considered exceptional for the nervous system of Vertebrates. DNA contents were correlated t o both nuclear and animal size. Utilization of AT and GC specific fluo rochromes showed that the increase in DNA content is due to differenti al genome amplification involving GC-rich DNA sequences.