Many human L1 elements are capable of retrotransposition

Nat Genet. 1997 May;16(1):37-43. doi: 10.1038/ng0597-37.


Using a selective screening strategy to enrich for active L1 elements, we isolated 13 full-length elements from a human genomic library. We tested these and two previously-isolated L1s (L1.3 and L1.4) for reverse transcriptase (RT) activity and the ability to retrotranspose in HeLa cells. Of the 13 newly-isolated L1s, eight had RT activity and three were able to retrotranspose. L1.3 and L1.4 possessed RT activity and retrotransposed at remarkably high frequencies. These studies bring the number of characterized active human L1 elements to seven. Based on these and other data, we estimate that 30-60 active L1 elements reside in the average diploid genome.

Publication types

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

MeSH terms

  • Animals
  • Chromosome Mapping
  • Chromosomes, Human*
  • Gene Frequency
  • Genome, Human
  • HeLa Cells
  • Humans
  • Mice
  • Molecular Sequence Data
  • RNA-Directed DNA Polymerase / genetics
  • RNA-Directed DNA Polymerase / metabolism
  • Repetitive Sequences, Nucleic Acid*
  • Retroelements / genetics*
  • Sequence Analysis, DNA


  • Retroelements
  • RNA-Directed DNA Polymerase

Associated data

  • GENBANK/U93562
  • GENBANK/U93563
  • GENBANK/U93564
  • GENBANK/U93565
  • GENBANK/U93566
  • GENBANK/U93567
  • GENBANK/U93568
  • GENBANK/U93569
  • GENBANK/U93570
  • GENBANK/U93571
  • GENBANK/U93572
  • GENBANK/U93573
  • GENBANK/U93574