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A census of mammalian imprinting
Ian M Morison1, Joshua P Ramsay, Hamish G Spencer
1Cancer Genetics Laboratory, Department of Biochemistry and National Research Centre for Growth and Development, University of Otago, PO Box 56, Dunedin, New Zealand. ian.morison@otago.ac.nz
Trends in Genetics : TIG
|July 2, 2005
Summary
Genomic imprinting silences specific genes, creating vulnerability. A census reveals 83 imprinted genes, with many differing between humans and mice, impacting mammalian evolution.
Area of Science:
- Genetics
- Evolutionary Biology
- Genomic Imprinting
Background:
- Genomic imprinting silences a small proportion of genes based on parent of origin.
- This process introduces hemizygosity, a vulnerability, into the diploid mammalian genome.
- Understanding imprinting is crucial for evaluating its biological and evolutionary significance.
Purpose of the Study:
- To create a comprehensive census of known imprinted genes.
- To facilitate the evaluation of the biological and evolutionary significance of genomic imprinting.
- To compare imprinted genes across species, specifically humans and mice.
Main Methods:
- Collated a census of known imprinted genes.
- Identified 83 transcriptional units as imprinted.
- Compared imprinting status between human and mouse orthologues.
Main Results:
- Identified 83 imprinted transcriptional units.
- Found 29 imprinted genes common to both humans and mice.
- Observed significant discordance in imprinting status between humans and mice, even for orthologous genes.
- Noted a high proportion of imprinted genes are noncoding RNAs or retrotransposed genes.
Conclusions:
- Genomic imprinting patterns show considerable divergence between humans and mice.
- Noncoding RNAs and retrotransposed genes are frequently imprinted.
- Further data accumulation is essential for understanding imprinting's role in mammalian evolution.