Courtney Griffin Explains Epigenetics

Dr. Courtney Griffin is now an Assistant Member in the Cardiovascular Biology Research Program at the Oklahoma Medical Research Foundation (OMRF) after receiving her B.A. from Harvard University and her Ph. D. from the University of California San Francisco School of Medicine.

Because we want to understand what genes are required for blood vessel development, Dr. Griffin studies certain enzymes that help turn genes on and off. These enzymes are specifically involved in relaxing DNA that is normally tightly coiled up in our cells.

In her laboratory at OMRF, Griffin is studying this emerging field, which is known as epigenetics.

In biology, and specifically genetics, epigenetics is the study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence – hence the name epi- (Greek: επί- over, above, outer) -genetics. It refers to functionally relevant modifications to the genome that do not involve a change in the nucleotide sequence. Examples of such changes are DNA methylation and histone deacetylation, both of which serve to suppress gene expression without altering the sequence of the silenced genes.

Epigenetic marks can be influenced by the environment.  This can include the enviroment outside of the embryonic environment.  These marks can also be transferred from generation to generation if the marks are put down on sperm or eggs. Griffin says, studies in Sweden and England have shown that behaviour such as smoking and overeating can have major impacts on future generations, sometimes dropping lifespan by decades

When you have children, you pass on that genetic information, along with your partner’s, to your children. While behavior during our lifetimes—diet, stress, inactivity—obviously affects our own health, scientists long believed that it had no impact on genetic materials we passed on to our offspring.

“That has changed,” says Griffin. “What we’re now learning is that the choices we make affect not only our own futures but also those of our children and grandchildren.”

“Epigenetic marks are chemical signals that tell the cell which genes should be turned on or shut off,” she said. “It turns out that all sorts of factors in our lives can alter our epigenetic marks, and we can pass those altered marks along to future generations.”

Griffin and Carol Curtis, Ph.D., a post-doctoral fellow at OMRF, recently published a paper on the role of epigenetics in the development of the vascular system. Their work, which appears in the journal Molecular and Cellular Biology, shows how competing epigenetic signals can affect the same cellular function.

Scientists are hoping these types of studies will lead to therapeutics that can alter epigenetic signals to turn on beneficial genes and suppress those that might cause harm. In the meantime, Griffin said it’s up to individuals to make lifestyle changes.

“It’s kind of freeing to know that we’re not locked into a predetermined genetic destiny. By making better choices now, you can help yourself, your future kids and their kids,” she said.  Below is the embedded TED video of Dr. Griffin's presentation at TEDxOU.