Telomere-Specialized Retroelements in Drosophila: Adaptive Symbionts of the Genome, Neutral, or in Conflict?

Bioessays. 2020 Jan;42(1):e1900154. doi: 10.1002/bies.201900154. Epub 2019 Dec 9.


Linear chromosomes shorten in every round of replication. In Drosophila, telomere-specialized long interspersed retrotransposable elements (LINEs) belonging to the jockey clade offset this shortening by forming head-to-tail arrays at Drosophila telomere ends. As such, these telomeric LINEs have been considered adaptive symbionts of the genome, protecting it from premature decay, particularly as Drosophila lacks a conventional telomerase holoenzyme. However, as reviewed here, recent work reveals a high degree of variation and turnover in the telomere-specialized LINE lineages across Drosophila. There appears to be no absolute requirement for LINE activity to maintain telomeres in flies, hence the suggestion that the telomere-specialized LINEs may instead be neutral or in conflict with the host, rather than adaptive.

Keywords: Drosophila; telomerase; telomere; telomere-elongating mechanisms; telomeric transposable elements; transposable element conflict.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Drosophila / genetics*
  • Genome, Insect*
  • Long Interspersed Nucleotide Elements
  • Retroelements / genetics*
  • Symbiosis
  • Telomerase / genetics
  • Telomerase / metabolism
  • Telomere / genetics*
  • Telomere / metabolism


  • Retroelements
  • Telomerase