Lessons from comparative analysis of species-specific imprinted genesOkamura K. · Ito T.
aDepartment of Genetics and Genomic Biology, The Hospital for Sick Children, Toronto (Canada);
Genomic imprinting is generally believed to be conserved in all mammals except for egg-laying monotremes, suggesting that it is closely related to placental and fetal growth. As expected, the imprinting status of most imprinted genes is conserved between mouse and human, and some are imprinted even in marsupials. On the other hand, a small number of genes were reported to exhibit species-specific imprinting that is not necessarily accounted for by either the placenta or conflict hypotheses. Since mouse and human represent a single, phylogenetically restricted clade in the mammalian class, a much broader comparison including mammals diverged earlier than rodents is necessary to fully understand the species-specificity and variation in evolution of genomic imprinting. Indeed, comparative analysis of a species-specific imprinted gene Impact using a broader range of mammals led us to propose an alternative dosage control hypothesis for the evolution of genomic imprinting.
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Department of Computational Biology
Graduate School of Frontier Sciences, University of Tokyo
5-1-5 Kashiwanoha, Kashiwa 277-8561 (Japan)
telephone: +81-4-7136-3989; fax: +81-4-7136-3979
Supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan.
Manuscript received: 31 May 2005
Accepted in revised form for publication by F. Ishino,: 1 September 2005.
Number of Print Pages : 6
Number of Figures : 2, Number of Tables : 0, Number of References : 53
Cytogenetic and Genome Research
Vol. 113, No. 1-4, Year 2006 (Cover Date: March 2006)
Journal Editor: Schmid, M. (Würzburg)
ISSN: 1424–8581 (print), 1424–859X (Online)
For additional information: http://www.karger.com/CGR