What if the choices we make during our lives altered our genes and affect our children?
Epigenetics, the study of changes in gene activity that do not involve alterations to the genetic code, may be the key to such knowledge.
Imprinted genes are similar to mutated genes, said Randy Jirtle, associate professor in the department of radiation oncology. One copy is functional while the other inherited copy is switched off by molecular markers from either parent, Jirtle added.
“These genes are controlled by the epigenome, which is the regulation of genes," Jirtle said. With these marks, environmental factors—including malnutrition—can imprint genes that will be inherited by the next generation"
This has been a revolutionary concept in its assertion that evolutionary changes can take place rather quickly. Previous theories, including Charles Darwin's, provided data that any effects of nurture on a species’ nature occur after many generations of natural selection.
Jirtle and other scientists have acquired enlightening data in the field of epigenetics, including Jirtle’s study demonstrating that malnutrition during pregnancy is adversely associated with the child’s susceptibility to diseases after birth.
Jirtle noted that the increased attention to epigenetics is in line with medicine’s shift from treatment to preventative measures.
“Prevention to a great degree will be nutritional. It will be significant to have nutritional departments work with medicine," Jirtle said.
In order to carry out most experiments for epigenetics, scientists have used DNA methylation—a process in which a molecule is added to DNA to inactivate a particular DNA fragment.
“DNA methylation is a powerful mechanism used to regulate gene expression,” said Susan Murphy, assistant professor of obstetrics and gynecology.
Murphy is currently studying how shifts in DNA methylation, resulting from nutrition and environmental exposures during pregnancy, change the way genes function and perhaps increase the baby’s risk of developing disorders.
The exciting aspect of this research is the future possibility that simple dietary modifications may allow us to prevent or even correct possible negative outcomes, Murphy noted.
Murphy hopes that eventually epigenetic information will be used to help with risk assessment in relation to human health. Epigenetic profiles provide important information regarding the suitability of particular drugs for treatment of diseases like cancer and better inform drug choice for tumors when performed prior to treatment, she added.
Because of the somewhat heretical nature of his work, Jirtle and others in his field have found some opposition from others.
“10 years ago, I was told that nobody at Duke is interested in epigenetics,” Jirtle said. “The degree to which those same people believe in epigenetics has improved inevitably throughout the years, but I don’t believe they are still enlightened by it.”
Murphy agrees that even though epigenetics is understudied, great strides made in recent years make the outlook hopeful.
“It has been great to see the groundswell of interest and improvements in technologies that have made it more accessible to researchers who may not have previously considered inclusion of studies on how epigenetics relates to their areas of research," Murphy said. "With advances in technology, it is now possible-albeit still expensive- to decipher the DNA methylation profile of an entire genome, base by base."
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