[Evolution of genomic imprinting in mammals: what a zoo!].
Genomic imprinting imposes an obligate mode of biparental reproduction in mammals. This phenomenon results from the monoparental expression of a subset of genes. This specific gene regulation mechanism affects viviparous mammals, especially eutherians, but also marsupials to a lesser extent. Oviparous mammals, or monotremes, do not seem to demonstrate monoparental allele expression. This phylogenic confinement suggests that the evolution of the placenta imposed a selective pressure for the emergence of genomic imprinting. This physiological argument is now complemented by recent genomic evidence facilitated by the sequencing of the platypus genome, a rare modern day case of a monotreme. Analysis of the platypus genome in comparison to eutherian genomes shows a chronological and functional coincidence between the appearance of genomic imprinting and transposable element accumulation. The systematic comparative analyses of genomic sequences in different species is essential for the further understanding of genomic imprinting emergence and divergent evolution along mammalian speciation.
Proudhon
Charlotte
C
UMR 3215/Inserm U934, Unité de génétique et biologie du développement, Institut Curie, 26 rue d'Ulm, Paris Cedex 05, France. Charlotte.Proudhon@curie.fr
Bourc'his
Déborah
D
D000818:Animals; D005075:Biological Evolution; D019175:DNA Methylation; D004251:DNA Transposable Elements; D044127:Epigenesis, Genetic / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D018392:Genomic Imprinting / Q000235:genetics; D006801:Humans; D008297:Male; D008322:Mammals / Q000196:embryology / Q000235:genetics*; D008394:Marsupialia / Q000196:embryology / Q000235:genetics; D051379:Mice / Q000196:embryology / Q000235:genetics; D010802:Phylogeny; D010920:Placenta / Q000502:physiology; D010987:Platypus / Q000196:embryology / Q000235:genetics; D011247:Pregnancy; D013045:Species Specificity; D014714:Vertebrates / Q000196:embryology / Q000235:genetics
D004251:DNA Transposable Elements