Chromatin remodeling: the interface between extrinsic cues and the genetic code?
The successful completion of the human genome project ushered a new era of hope and skepticism. However, the promise of finding the fundamental basis of human traits and diseases appears less than fulfilled. The original premise was that the DNA sequence of every gene would allow precise characterization of critical differences responsible for altered cellular functions. The characterization of intragenic mutations in cancers paved the way for early screening and the design of targeted therapies. However, it has also become evident that unmasking genetic codes alone cannot explain the diversity of disease phenotypes within a population. Further, classic genetics has not been able to explain the differences that have been observed among identical twins or even cloned animals. This new reality has re-ignited interest in the field of epigenetics. While traditionally defined as heritable changes that can alter gene expression without affecting the corresponding DNA sequence, this definition has come into question. The extent to which epigenetic change can also be acquired in response to chemical stimuli represents an exciting dimension in the "nature vs nurture" debate. In this review I will describe a series of studies in my laboratory that illustrate the significance of epigenetics and its potential clinical implications.
Ezzat
Shereen
S
Department of Medicine, Princess Margaret Hospital, Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada. shereen.ezzat@utoronto.ca
D000818:Animals; D042002:Chromatin Assembly and Disassembly; D019976:Cloning, Organism; D044127:Epigenesis, Genetic; D005815:Genetic Code; D015894:Genome, Human; D016045:Human Genome Project; D006801:Humans; D010641:Phenotype; D040641:Quantitative Trait Loci; D018433:Twin Studies as Topic