We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Medical News & Perspectives |

Randy L. Jirtle, PhD

Bridget M. Kuehn
JAMA. 2008;299(11):1249-1250. doi:10.1001/jama.299.11.1249.
Text Size: A A A
Published online


Scientists studying one facet of how gene activity is orchestrated may be starting to unravel the mystery of how genes interact with the environment to cause disease. They have found that many of these changes are epigenetic in nature. Epigenetic changes may be thought of as chemical switches that can turn on and off the expression of genes in response to environmental factors.

Randy L. Jirtle, PhD, of Duke University Medical Center in Durham, NC, explained that epigenetic changes may allow species to adapt rapidly in response to environmental signals early in life. But some epigenetic changes can increase risk of disease if they lead to dysregulation of genes or if there is a mismatch between the environment during development and the environment encountered in adulthood.

Figures in this Article

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

First Page Preview

View Large
First page PDF preview


Place holder to copy figure label and caption

Graphic Jump LocationImage not available.

Chemical changes to DNA, such as the addition of methyl groups (pictured), may alter gene expression without altering the gene’s DNA sequence.

(Credit: David J. Blum)



Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

5 Citations

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles Related By Topic
Related Collections
PubMed Articles