We shall study the sequence of Rous sarcoma virus, the splicing of viral messengers, and the use of RSV sequences as parts of eukaryotic vector system. We shall study murine leukemia virus integration sites. We shall study the murine leukemia virus integration sites. We shall study the structure of the genes for the glycolytic enzymes triose phosphate isomerase and pyruvate kinase from vertebrates. We shall examine messenger RNA splicing in yeast mitochondria.