title: The problematic in-vitro embryo in the age of epigenetics.
abstract: During use of many assisted reproductive technologies, the embryo spends time in vitro. The immediate and long-term epigenetic impacts of this exposure to an in-vitro environment are discussed in the context of the health of the offspring. Three exemplary types of possible epigenetic impact are discussed: embryonic cell numbers, mitochondria, and genomic imprints. There is evidence that all of these can be affected in the short term and that these short-term impacts can have heritable consequences across developmental cell generations into maturity. There is also evidence of association between the observed impact and pathology, but as yet no unequivocal evidence of causality for humans and mice. The problematic in-vitro embryo is considered paradigmatic for a central question facing biology: how does the environment interact epigenetically with the genome to produce variable phenotypic outcomes?
authors.affiliation: Department of Anatomy, Downing Street, Cambridge CB2 3DY, UK. mhj@mole.bio.cam.ac.uk
authors.forename: Martin H
authors.initials: MH
authors.lastname: Johnson
mesh_terms: D000220:Adaptation, Biological; D001755:Blastocyst / Q000502:physiology*; D046149:Embryo Culture Techniques / Q000941:ethics; D044127:Epigenesis, Genetic; D005260:Female; D005307:Fertilization in Vitro / Q000941:ethics*; D018392:Genomic Imprinting; D006801:Humans; D008928:Mitochondria; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects