Small variations in our DNA can correlate with individual differences in response to a medication or disease risk. In many cases, these variations occur within the DNA sequences of our genes and influence how the gene's products work.
Changing the DNA sequence isn't the only way to affect a gene, though. Altering the level of gene expression - thus increasing or decreasing the amount of RNA or protein made - can influence biological processes just as dramatically.
Gene expression and obesity
Let's look at obesity as an example of how gene expression can correlate with disease risk:
Obesity is a major health risk in America that threatens children and adults alike. It can lead to heart disease, high blood pressure and diabetes, especially as people age. A complex medical condition, obesity is influenced by diet, exercise, metabolism - and genetics.
Shan, age 17, is more than 40 pounds overweight relative to his height. His parents and grandparents are all overweight as well.
Allen is similar to Shan with respect to age, height, diet and exercise habits, but he is not overweight. Furthermore, no one in Allen's family is overweight.
Both Shan's and Allen's families volunteer to participate in a university study to identify genes that play a role in obesity. How will the researchers approach this question?
Measuring levels of gene expression
Three generations of family members provide cell samples (liver and fat cells) to the researchers. Liver and fat cells were chosen because they are important in metabolism and making fats.
Once the scientists compare the results from everyone in the study, they have a good idea which genes play a role in obesity. This information will be used in several future applications:
Supported by a Science Education Partnership Award (SEPA) [No. 1 R25 RR16291-01] from the National Center for Research Resources, a component of the National Institutes of Health, Department of Health and Human Services. The contents provided here are solely the responsibility of the authors and do not necessarily represent the official views of NCRR or NIH.