The molecular basis of I-R hybrid dysgenesis in Drosophila melanogaster: identification, cloning, and properties of the I factor

Cell. 1984 Aug;38(1):153-63. doi: 10.1016/0092-8674(84)90536-1.


We have analyzed two mutations of the white-eye gene, which arose in flies subject to I-R hybrid dysgenesis. These mutations are associated with insertions of apparently identical 5.4 kb sequences, which we have cloned. We believe that these insertions are copies of the I factor controlling I-R hybrid dysgenesis. The I factor is not a member of the copia-like or fold-back classes of transposable elements and has no sequence homology with the P factor that controls P-M dysgenesis. All strains of D. melanogaster contain I-factor sequences. Those present in reactive strains must represent inactive I elements. I elements have a remarkably similar sequence organization in all reactive strains and are located in peri-centromeric regions. Inducer strains appear to contain both I elements, located in peri-centromeric regions, and 10-15 copies of the complete I factor at sites on the chromosome arms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Chromosomes / ultrastructure
  • Cloning, Molecular*
  • Crosses, Genetic
  • DNA / isolation & purification
  • DNA Restriction Enzymes
  • DNA Transposable Elements*
  • Drosophila melanogaster / genetics*
  • Female
  • Male
  • Mutation*
  • Nucleic Acid Hybridization
  • Plasmids


  • DNA Transposable Elements
  • DNA
  • DNA Restriction Enzymes