Environmental effects on genomic imprinting in mammals

Genomic imprinting is an epigenetic marking mechanism by which certain gene s become repressed on one of the two parental alleles. Imprinting plays imp ortant roles in mammalian development, and in humans its deregulation may r esult in disease and carcinogenesis. During different medical, technologica l and scientific interventions, pre-implantation embryos and cells are take n from their natural environment and subjected to culture in artificial med ia. Studies in the mouse demonstrate that environmental stress. such as in vitro culture. can affect the somatic maintenance of epigenetic marks at im printed loci. These effects are associated with aberrant growth and morphol ogy at fetal and perinatal stages of development. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.