Genetic effects of injection of Rous sarcoma virus DNA into polar plasm of early Drosophila melanogaster embryos [Microinjection technique]

Retroviral proviruses and the transposable elements of eukaryotic genomes are structurally similar 1–3 . The biological significance of eukaryotic transposable elements has not been examined extensively but it is known that, like prokaryotic transposons, these elements can induce mutations in adjacent genes and cause their transposition 4,5 . It is of interest to determine whether retroviral proviruses have the same mutagenic 6 and gene transposing ability as transposable elements, particularly because the retrovirus genome is assumed to have originated from transposable elements of lower eukaryotes 1 . The transfer of DNA sequences into animal zygotes or embryos by microinjection is a promising experimental approach for eluxidating their functions 7–11 : when foreign DNAs were introduced into a mouse germ line, mutations were induced 9–11 and at least in some mice, the mutation was caused by the insertion of a retroviral sequence 9,10 . We have introduced Rous sarcoma virus (RSV) DNA into a germ line of Drosophila melanogaster , and describe here the resultant genetic effects.