Prokaryotes possible progression 269

In spite of recent progress toward elucidation of the mechanism of nuclear envelope formation In modern eukaryotes, evolutionary origins of the eukaryote nucleus remain obscure. Even the concept of nuclear envelope organization around annulae derived from preexisting annulae offers little to help select among the various possibilities. Yet, similarities of Inner membrane of the nuclear envelope and the procaryotic cell membrane argue for a common parallel evolution of these two membrane types. For example, the Inner nuclear membrane Is associated with DNA (i) and perhaps even with DNA replication 21, 23) as In bacterial cells (J). There was even a report that It contained cytochrome oxidase 20), an enzyme associated with the plasma membrane of prokaryotes and critical to the development of aerobic metabolism. 

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