Molecular characteristics of the heterochromatic I elements from a reactive strain of Drosophila melanogaster

J Mol Evol. 1990 Nov;31(5):424-31. doi: 10.1007/BF02106056.


There are two categories of strains in Drosophila melanogaster with respect to the I-R system of hybrid dysgenesis. The inducer strains contain particular transposable elements named I factors. They are not present in the strains of the other category called reactive (R) strains. Defective I elements are present in the pericentromeric regions of both categories of strains. This last subfamily of I sequences has not yet been described in detail and little is known about its origin. In this paper, we report that the defective I elements display an average of 94% of sequence identity with each other and with the transposable I factor. The results suggest that they cannot be the progenitors of the present day I factors, but that each of these two subfamilies started to evolve independently several million years ago. Furthermore, the sequence comparison of these I elements with an active I factor from Drosophila teissieri provides useful information about when the deleted I elements became immobilized.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Biological Evolution*
  • DNA Transposable Elements*
  • Drosophila melanogaster / genetics*
  • Heterochromatin / chemistry*
  • Molecular Sequence Data
  • Mutation
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid


  • DNA Transposable Elements
  • Heterochromatin