Convergent and divergent evolution of genomic imprinting in the marsupial Monodelphis domesticaReportar como inadecuado

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BMC Genomics

, 13:394

First Online: 16 August 2012Received: 18 April 2012Accepted: 09 August 2012DOI: 10.1186-1471-2164-13-394

Cite this article as: Das, R., Anderson, N., Koran, M.I. et al. BMC Genomics 2012 13: 394. doi:10.1186-1471-2164-13-394


BackgroundGenomic imprinting is an epigenetic phenomenon resulting in parent-of-origin specific monoallelic gene expression. It is postulated to have evolved in placental mammals to modulate intrauterine resource allocation to the offspring. In this study, we determined the imprint status of metatherian orthologues of eutherian imprinted genes.

ResultsL3MBTL and HTR2A were shown to be imprinted in Monodelphis domestica the gray short-tailed opossum. MEST expressed a monoallelic and a biallelic transcript, as in eutherians. In contrast, IMPACT, COPG2, and PLAGL1 were not imprinted in the opossum. Differentially methylated regions DMRs involved in regulating imprinting in eutherians were not found at any of the new imprinted loci in the opossum. Interestingly, a novel DMR was identified in intron 11 of the imprinted IGF2R gene, but this was not conserved in eutherians. The promoter regions of the imprinted genes in the opossum were enriched for the activating histone modification H3 Lysine 4 dimethylation.

ConclusionsThe phenomenon of genomic imprinting is conserved in Therians, but the marked difference in the number and location of imprinted genes and DMRs between metatherians and eutherians indicates that imprinting is not fully conserved between the two Therian infra-classes. The identification of a novel DMR at a non-conserved location as well as the first demonstration of histone modifications at imprinted loci in the opossum suggest that genomic imprinting may have evolved in a common ancestor of these two Therian infra-classes with subsequent divergence of regulatory mechanisms in the two lineages.

KeywordsGenomic imprinting Marsupials Eutherians AbbreviationsDMRDifferentially methylated region

H3K4me2Histone3 Lysine4 dimethylation

H3K9me3Histone3 Lysine9 trimethylation.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2164-13-394 contains supplementary material, which is available to authorized users.

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Autor: Radhika Das - Nathan Anderson - MaryEllen I Koran - Jennifer R Weidman - Tarjei S Mikkelsen - Michael Kamal - Susan K M


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