Sexual reproduction yields offspring with two copies of the same gene, one from each parent; but in an epigenetic phenomenon known as genomic imprinting, only one copy of certain genes is turned on or off, depending on which parent contributed it. Imprinted genes are stamped by patterns of DNA methylation or histone modification during gamete formation, and their activation or inactivation is then passed on to offspring. Previously, approximately 100 genes were thought to be imprinted in mammals. But Rutgers University molecular biologist and F1000 Member Joachim Messing, discusses a recent paper that found many more imprinted genes in mammals, suggesting this may be a major form of epigenetic regulation (Science, 329:643-48, 2010).
The Scientist: What’s an evolutionary justification for the parental bias in gene ...
