A census of mammalian imprinting

Trends Genet. 2005 Aug;21(8):457-65. doi: 10.1016/j.tig.2005.06.008.


Genomic imprinting, the parent-of-origin-specific silencing of a small proportion of genes, introduces a paradoxical vulnerability of hemizygosity into the diploid mammalian genome. To facilitate the evaluation of the biological and evolutionary significance of imprinting, we have collated a census of known imprinted genes, listing 83 transcriptional units of which 29 are imprinted in both humans and mice. There is a high level of discordance of imprinting status between the mouse and human, even when cases in which the orthologue is absent from one species are excluded. A high proportion of imprinted genes are noncoding RNAs or genes derived by retrotransposition. Accumulation of functional and comparative data for these genes will improve our understanding of imprinting and its contribution to mammalian evolution.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Evolution, Molecular
  • Female
  • Genomic Imprinting*
  • Humans
  • Introns
  • Male
  • Mice
  • Models, Genetic
  • RNA, Untranslated / genetics
  • Retroelements / genetics
  • Species Specificity
  • Transcription, Genetic


  • RNA, Untranslated
  • Retroelements