Oxytricha in many ways has a typical eukaryotic genome, at the same time it is a hypotrichous ciliated protozoan displaying a highly unusual DNA metabolism: its macronucleus is generated by a specific fragmentation and genetic diminution process which results in the retention of only about 10% of the total Osytricha sequence complexity; these remaining sequences exist as small gene-sized fragments which provide all RNA transcripts necessary for vegetative growth. Thus, the macronuclear DNAs and the process by which they are generated provide a unique opportunity to study eurkaryotic gene and gemone structural organization, respectively. We have recently identified and characterized a highly repetitious sequence found on every gene piece. Much of the proposed work centers on further characterization of DNA structural features common to all gene pieces; the work uses in vitro DNA recombinants, DNA sequencing high resolution gel electrophoresis, nucleic acid hybridization and electron microscopy. To complement these rapidly developing tools of DNA technology, I have begun to develop a DNA-affinity chromatography procedure to allow the identification and purification of sequence-specific DNA-binding proteins which bind to DNA sequences of interest. I intend to use this technique to elucidate the functions of various fascinating features of Osytricha DNA; I also expect this technique to have wide application in a number of the other molecular biology systems.