Paramutation: an encounter leaving a lasting impression.
Paramutation is the result of heritable changes in gene expression that occur upon interaction between alleles. Whereas Mendelian rules, together with the concept of genetic transmission via the DNA sequence, can account for most inheritance in sexually propagating organisms, paramutation-like phenomena challenge the exclusiveness of Mendelian inheritance. Most paramutation-like phenomena have been observed in plants but there is increasing evidence for its occurrence in other organisms, including mammals. Our knowledge of the underlying mechanisms, which might involve RNA silencing, physical pairing of homologous chromosomal regions or both, is still limited. Here, we discuss the characteristics of different paramutation-like interactions in the light of arguments supporting each of these alternative mechanisms.
Stam
Maike
M
Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands. mstam@science.uva.nl
Mittelsten Scheid
Ortrun
O
D000483:Alleles; D044127:Epigenesis, Genetic; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D017343:Genes, Plant / Q000502:physiology; D008957:Models, Genetic; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics; D010944:Plants / Q000235:genetics*
D010940:Plant Proteins