Differences in gene expression levels between people of European versus African ancestry can affect how each group responds to certain drugs or fights off specific infections, report researchers from the University of Chicago Medical Center and the Expression Research Laboratory at Affymetrix Inc. of Santa Clara, CA.
In the March 7, 2008, print issue of American Journal of Human Genetics, and published early online, the researchers used Affymetrix exon arrays to show that expression levels for nearly five percent of the 9,156 human genes they studied varied significantly between individuals of European and African ancestry. The research team took an unbiased whole genome approach and found significant differences in several unrelated processes, especially among genes involved in producing antibodies to potential microbial invaders.
The researchers used lymphoblastoid cell lines derived from blood from 180 healthy individuals. They studied 60 nuclear families, including mother, father and child. Thirty of the families were Caucasians from Utah and 30 were Yorubans from Ibadan, Nigeria.
"Our primary interest is the genes that regulate how people respond to medicines, such as cancer chemotherapy," said cancer specialist Eileen Dolan, PhD, professor of medicine at the University of Chicago and senior author of the study. "We want to understand why different populations experience different degrees of toxicity when taking certain drugs and learn how to predict who might be most at risk for drug side effects."
But in the process they saw several other differences. Some, including variation in the immune system's response to microbial invaders, were expected. Previous studies have found that African Americans may be more susceptible than Caucasians to infection by certain bacteria, such as Porphyromonas gingivalis that causes periodontitis.