Mammalian Genome

, Volume 17, Issue 2, pp 157–167

Comparative phylogenetic analysis reveals multiple non-imprinted isoforms of opossum Dlk1

  • Jennifer R. Weidman
  • Kristin A. Maloney
  • Randy L. Jirtle
Article

DOI: 10.1007/s00335-005-0116-x

Cite this article as:
Weidman, J.R., Maloney, K.A. & Jirtle, R.L. Mamm Genome (2006) 17: 157. doi:10.1007/s00335-005-0116-x
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Abstract

Imprinted genes are monoallelically expressed in a parent-of-origin manner and were previously identified in both marsupials and eutherians, but not in monotremes. Phylogenetic comparison of imprinted domains is a powerful tool for investigating the molecular and adaptive evolution of this unique gene regulatory mechanism. Herein, we report that multiple transcripts of Dlk1 (Delta, Drosophila, Homolog-like 1) are expressed in the opossum, but none are imprinted. Thus, we provide the first example of a reciprocally imprinted gene domain in which imprinting evolved in a common ancestor to eutherian rather than therian mammals. Moreover, the reciprocally imprinted Meg3 (Maternally Expressed Gene 3), found downstream of Dlk1 in eutherian mammals, is absent in the opossum. We propose that the Meg3 sequence integrated into the eutherian Dlk1 domain via a LINE-1 element and that Dlk1 became imprinted in eutherian mammals only after this downstream integration. These findings clearly demonstrate that imprinted genes did not all evolve before the divergence of marsupials and eutherians.

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • Jennifer R. Weidman
    • 1
    • 2
  • Kristin A. Maloney
    • 1
    • 2
    • 3
  • Randy L. Jirtle
    • 1
    • 2
    • 3
    • 4
  1. 1.Department of Radiation OncologyDuke University Medical CenterDurhamUSA
  2. 2.University Program in Genetics and GenomicsDuke University Medical CenterDurhamUSA
  3. 3.Program in Cell and Molecular BiologyDuke University Medical CenterDurhamUSA
  4. 4.Duke University Medical CenterDurhamUSA

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