Abstract
Sequences homologous to the oncogene sequences of acute RNA tumor viruses are highly conserved within vertebrates. Eight different oncogene DNA sequences were used as probes to search for homologous sequences in the DNA of organisms of other phyla. Five of these probes hybridized to the DNA of D. melanogaster. Abelson leukemia virus probe detected a single homologous DNA fragment in Drosophila DNA. Probes prepared from the genomes of Harvey, avian and feline sarcoma viruses and avian myelocytomatosis virus hybridized with multiple homologous sequences in Drosophila DNA. The identification of sequences homologous to vertebrate oncogenes in invertebrates demonstrates both a high degree of conservation of these genes and a wide distribution among divergent species. Sequences homologous to vertebrate oncogenes may play a crucial role in metazoan metabolism.